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Overview

Brief Summary

History in the United States

Purple loosestrife was introduced to the northeastern U.S. and Canada in the 1800s, for ornamental and medicinal uses. It is still widely sold as an ornamental, except in states such as Minnesota, Wisconsin, and Illinois where regulations now prohibit its sale, purchase and distribution.

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History in the United States

Purple loosestrife was introduced to the northeastern United States and Canada in the 1800s for ornamental and medicinal uses. It is still widely sold as an ornamental, except in states such as Minnesota, Wisconsin and Illinois where regulations now prohibit its sale, purchase and distribution. Purple loosestrife adapts readily to natural and disturbed wetlands.

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Comprehensive Description

Description

General: Loosestrife Family (Lythraceae). Purple loosestrife is an erect perennial herb that grows up to 2.5 m tall, develops a strong taproot, and may have up to 50 stems arising from its base. Its 50 stems are four-angled and glabrous to pubescent. Its leaves are sessile, opposite or whorled, lanceolate (2-10 cm long and 5-15 mm wide), with rounded to cordate bases. Leaf margins are entire. Leaf surfaces are pubescent.

Each inflorescence is spike-like (1-4 dm long), and each plant may have numerous inflorescences. The calyx and corolla are fused to form a floral tube (also called a hypanthium) that is cylindrical (4-6 mm long), greenish, and 8-12 nerved. Typically the calyx lobes are narrow and thread-like, six in number, and less than half the length of the petals. The showy corolla (up to 2 cm across) is rose-purple and consists of five to seven petals. Twelve stamens are typical for each flower. Individual plants may have flowers of three different types classified according to stylar length as short, medium, and long. The short-styled type has long and medium length stamens, the medium type has long and short stamens, and the long-styled has medium to short stamens. The fruit is a capsule about 2 mm in diameter and 3-4 mm long with many small, ovoid dust-like seeds (< 1 mm long).

Mal et al., 1992, provide a detailed morphological description for L. salicaria. The authors also give details of the tristylous features of this species, as well as an account of its pollen structure and chromosome numbers. The plant’s habit, vegetative, and reproductive structures are illustrated with line drawings.

Other species of Lythrum that grow in the United States have 1-2 flowers in each leaf-like inflorescence bract and eight or fewer stamens compared to L. salicaria, which has more than two flowers per bract and typically twelve stamens per flower. Lythrum virgatum, another species introduced from Europe closely resembles L. salicaria, but differs in being glabrous (lacking plant hairs), and having narrow leaf bases. The latter two species interbreed freely producing fertile offspring, and some taxonomists (Rendall 1989) consider them to be a single species.

Distribution: Purple loosestrife is a hardy perennial herb with stunning spikes of purple flowers. A native of Eurasia, it was introduced to North America in the early 1800's where it first appeared in ballast heaps of eastern harbors (Stuckey 1980). Most likely seeds were transported as contaminants in the ballast or possibly attached to raw wool or sheep imported from Europe (Cole, 1926; Thompson et al., 1987).

The native range of L. salicaria is thought to extend from Great Britain to central Russia from near the 65th parallel to North Africa. It also occurs in Japan, Korea, and the northern Himalayan region. The species has been introduced to Australia, Tasmania, and New Zealand. Since its introduction to North America, this alien plant has spread rapidly into Canada, and throughout most of the United States where it has been reported from all states except Alaska, Florida, Louisiana, and South Carolina. Several factors have contributed to the spread of purple loosestrife such as its potential for rapid growth, its enormous reproductive capacity, lack of natural diseases or predators, its use as an ornamental, and for bee forage (Mal et al. 1992). For current U.S. distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

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USDA NRCS National Plant Data Center & Louisiana State University-Plant Biology; partial funding from the US Geological Survey and the US National Biological Information Infrastructure

Source: USDA NRCS PLANTS Database

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Alternative names

purple loosestrife, spiked lythrum, salicaire, bouquet violet

Public Domain

USDA NRCS National Plant Data Center & Louisiana State University-Plant Biology; partial funding from the US Geological Survey and the US National Biological Information Infrastructure

Source: USDA NRCS PLANTS Database

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Comments

The only other species that is similar to Purple Loosestrife is the native Lythrum alatum (Winged Loosestrife), which also occurs in wetlands. This latter species is a smaller and less aggressive plant with winged stems, while the stems of Purple Loosestrife are usually round (sometimes 4-angled). Their flowers are similar in appearance, although Winged Loosestrife has smaller flowers (½" across or less).
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© John Hilty

Source: Illinois Wildflowers

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Description

This introduced perennial plant is 2-5' tall, branching frequently below the inflorescence. The stems are variably hairy, becoming woody and glabrous below. The leaves are usually opposite, less often whorled in 3's; some of the upper leaves in the inflorescence may be alternate. These leaves are up to 4" long and ¾" across, becoming smaller as they ascend the stems. They are lanceolate, smooth along the margins, slightly hairy (especially the upper leaves), and clasp the stems. The upper stems terminate in long spikes of flowers about ½–2' long.  Each flower is about ½–1" across, consisting of 6 purple petals, a green tubular calyx, 6 or more stamens, and a pistil with a stigma that is green and knobby. Each wrinkly petal has a dark purple line toward its base. The hairy calyx has 5 teeth at its apex and several veins along its length. Sometimes the flowers have fewer than 6 petals, and the relative length of their pistils and stamens is variable (in this regard, there are 3 different forms of flowers). The flowers are sessile against the flowering stalks, or they have very short pedicels. The blooming period occurs from mid-summer to early fall, and lasts about 2 months. Each flower is replaced by a small seed capsule that is surrounded by the tubular calyx. This capsule contains many tiny seeds that can float on water or be blown about by the wind. The root system is shallow and fibrous, frequently forming offsets by rhizomes. This plant often forms colonies, and can spread by its seeds, rhizomes, or segments of the roots and stems.
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Distribution

Range Description

This species is native throughout Europe and North Africa east through Turkey, Palestine and Lebanon to China, Japan and Korea. It has been introduced to North America and Australia where it can be extremely invasive. In Europe, it has been recorded from all countries except the Faroe Islands, Gibraltar (UK), Greek Aegean Islands, Crete, Cyprus, Iceland, Monaco, Azores, Madeira, Selvagens Islands, Russian Franz Josef Land and Novaya Zemlya, San Marino, Balearic Islands, Canary Islands and Svalbard and Jan Mayen (Norway).


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National Distribution

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

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More info for the term: marsh

Purple loosestrife occurs in all but 6 states of the continental United States [132]. It is found along the Atlantic coast from North Carolina to Maine [129] and is scattered but spreading in the western United States [81]. Purple loosestrife occurs most commonly in the United States in the Midwest and Northeast, corresponding closely with the geographic extent of the Wisconsin glaciation [81,125]. It is distributed across the southernmost tier of Canadian provinces from Newfoundland to British Columbia, with northern limits generally around 51° N [79]. The greatest concentrations in Canada are in southwestern Quebec, southern Ontario, southern Manitoba, and in British Columbia's lower Fraser Valley [46]. The Plants Database provides a map to purple loosestrife's distribution in the United States.

Considered native to Eurasia [125], purple loosestrife has a widespread circumpolar distribution throughout the northern hemisphere, except in extremely cold and arctic regions [111,129]. Although the precise origin of purple loosestrife colonization in North America is unknown, it was well established by the 1830s within coastal wetlands along the New England seaboard, having likely been introduced via ship ballast soil. Further introductions are thought to have occurred intentionally by early American horticulturalists. Initial spread of purple loosestrife into the interior of eastern North America occurred primarily via routes of maritime commerce, such as canals, rivers and the Great Lakes. Spread into the arid West appears to be closely related to development of irrigation systems within that region [129].

The following biogeographic classification systems are presented as a guide to demonstrate where purple loosestrife could potentially be found based on reported occurrence and on biological tolerance to factors likely to limit its distribution. For instance, because purple loosestrife does not tolerate salt water, classifications describing a variety of salt marsh habitats are excluded from these lists. Additionally, many of these classifications are named for predominantly upland habitats that nevertheless contain sometimes-substantial wetland areas where purple loosestrife could potentially occur. Precise distribution information is lacking because of gaps in the understanding of biological and ecological characteristics of non-native species and because introduced species may still be expanding their habitable range. Therefore these lists are speculative and may not be complete.

  • 79. Mal, Tarun K.; Lovett-Doust, Jon; Lovett-Doust, Lesley; Mulligan, G. A. 1992. The biology of Canadian weeds. 100. Lythrum salicaria. Canadian Journal of Plant Science. 72(4): 1305-1330. [37554]
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 125. Stuckey, Ronald L. 1980. Distributional history of Lythrum salicaria (purple loosestrife) in North America. Bartonia. 47: 3-20. [40053]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 46. Haber, Erich. 2001. Invasive plant data summary and control options: Purple loosestrife. In: Invasive plants of Canada: Guide to species and methods of control, [Online]. Available: http://www.magi.com/%%7Eehaber/lyth_sal.html [2002, January 25]. [40051]
  • 81. Malecki, Richard. 1995. Purple loosestrife. In: Non-native species. In: Laroe, Edward T.; Farris, Gaye S.; Puckett, Catherine E.; [and others], eds. Our living resources: a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems, [Online]. Washington, DC: U.S. Department of the Interior, National Biological Service (Producer). Available: http://biology.usgs.gov/s+t/noframe/x193.htm [2002, February 6]. [39788]
  • 132. U.S. Department of Agriculture, Natural Resources Conservation Service. 2008. PLANTS Database, [Online]. Available: http://plants.usda.gov/. [34262]

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Regional Distribution in the Western United States

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [16]:

1 Northern Pacific Border

2 Cascade Mountains

3 Southern Pacific Border

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

7 Lower Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

13 Rocky Mountain Piedmont

14 Great Plains

15 Black Hills Uplift

16 Upper Missouri Basin and Broken Lands
  • 16. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434]

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Occurrence in North America

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Distribution in the United States

According to the U.S. Fish and Wildlife Service, purple loosestrife now occurs in every state except Florida.

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Native Range

Eurasia; throughout Great Britain, and across central and southern Europe to central Russia, Japan, Manchuria China, southeast Asia and northern India 
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Distribution and Habitat in the United States

According to the U.S. Fish and Wildlife Service, purple loosestrife now occurs in every state except Florida. It is found in many types of wetlands, including wet freshwater meadows, tidal and non-tidal marshes, river and stream banks, pond edges, reservoirs and ditches.

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Origin

Eurasia

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Distribution: Europe, South-East and Central Asia, Siberia, North Africa, North America, Australia.
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Physical Description

Morphology

Description

Perennial herbs or subshrubs, 0.3-1.5 m tall, scabrous or sparsely to densely gray pubescent [or tomentose], sometimes somewhat glabrescent. Stem erect, 4-angled. Leaves opposite or 3-whorled, sometimes alternate toward stem apex, ovate-lanceolate to broadly lanceolate, 2.5-10 × 0.5-1.5 cm, base rounded, truncate, or semiclasping, apex acute to subobtuse. Inflorescences terminal, spicate, 15-35 cm; bracts broadly lanceolate or deltoid-ovate. Flowers in 1- to multi-flowered whorled axillary cymes, shortly pedicellate. Floral tube 5-8 × 1.5-2 mm, 12-ribbed; sepals deltate, 0.5-1 mm; epicalyx segments erect, linear, 1.5-2 mm, much longer than sepals. Petals reddish purple to rose-purple, lanceolate-oblanceolate, 7-10 × 1.5-3 mm. Fl. Jul-Sep, fr. Oct. 2n = 30, 50, 58, 60.
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Description

Perennial, 40-70 cm tall. Leaves ovate-lanceolate, elliptic or lanceolate, acute to acuminate, base cordate-amplexicaul, 6-60 mm long, 2.5-15 mm broad. Spikes 9-45 cm long. Pedicels 1-2 mm. Hypanthium 12-ribbed. Epicalyx longer than or equalling the calyx. Petals 5.5-8.5 mm long, 2-3 mm broad, obovate-spathulate or obovate-oblanceolate. Ovary subsessile, 2-5 mm long, 0.75-1.5 mm broad. Capsule 4 mm long, 1.5 mm broad, narrowed. Seeds obovate, tip ±membranous.
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Description

More info for the term: rootstock

Purple loosestrife is a non-native, perennial wetland herb [14,129]. Stems are erect, 1 to 8 feet (0.3-2.4 m) tall, becoming woody with age and persisting through winter and up to 2 years [9,14,73,118]. Mature, long-established plants are often 10 feet (3 m) tall and 5 feet (1.5 m) wide [129]. Plants may become increasingly bush-like by producing greater numbers of basal stems from the same rootstock each year [14,79,118,129]. Plants begin producing multiple stems from a single rootstock as early as the 2nd growing season [102]. Anderson [1] recorded single genets with over 130 stems produced from a single rootstock during a single season. He also estimated ages for individual plants up to 22 years. Observations have been recorded of particular rootstocks failing to generate shoots during a given year, but producing aboveground growth during each prior and subsequent season  [129].

Leaves are 2 to 6 inches (5-14 cm) long and attached close to the stem [14]. Flower spikes vary in length from > 40 inches (1 m) to only a few inches, and only 2 to 3 inches (5.1-7.6 cm) of the spike typically display open flowers at any given time [9,73]. Fruits are capsules 2-3 mm in length [56]. Seeds measure approximately 400 x 200 microns, and weigh approximately 1.8 x 10-6 ounces (50 µg) per seed, which is comparatively quite small among North American temperate wetland plants [116,129].

Seedlings quickly develop a thick, hardened taproot [111]. Mature plants subjected to persistent flooding respond by forming aerenchymous (containing large intercellular air spaces) tissue, permitting oxygen flow to submerged roots [118].

The preceding description provides characteristics of purple loosestrife that may be relevant to fire ecology and is not meant to be used for identification. Keys for identifying purple loosestrife are available in various floras (e.g. [57,71]). Photos and descriptions of purple loosestrife are also available online from Minnesota Sea Grant. Check with the native plant society or cooperative extension service in your area for more information.

  • 1. Anderson, Mark G. 1991. Population structure of Lythrum salicaria in relation to wetland community structure. Durham, NH: University of New Hampshire. 93 p. Thesis. [39754]
  • 9. Balogh, Gregory Robert. 1986. Ecology, distribution, and control of purple loosestrife (Lythrum salicaria) in northwest Ohio. Columbus, OH: Ohio State University. 122 p. Thesis. [40074]
  • 14. Benefield, Carri. 2000. Lythrum salicaria L. In: Bossard, Carla C.; Randall, John M.; Hoshovsky, Marc C., eds. Invasive plants of California's wildlands. Berkeley, CA: University of California Press: 236-240. [38336]
  • 56. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. [21992]
  • 57. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. [1168]
  • 73. Levin, Donald A.; Kerster, Harold W. 1973. Assortative pollination for stature in Lythrum salicaria. Evolution. 27: 144-152. [39778]
  • 79. Mal, Tarun K.; Lovett-Doust, Jon; Lovett-Doust, Lesley; Mulligan, G. A. 1992. The biology of Canadian weeds. 100. Lythrum salicaria. Canadian Journal of Plant Science. 72(4): 1305-1330. [37554]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 116. Shipley, B.; Parent, M. 1991. Germination responses of 64 wetland species in relation to seed size, minimum time to reproduction and seedling relative growth rate. Functional Ecology. 5(1): 111-118. [14554]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 71. Larson, Gary E. 1993. Aquatic and wetland vascular plants of the Northern Great Plains. Gen. Tech. Rep. RM-238. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 681 p. Jamestown, ND: Northern Prairie Wildlife Research Center (Producer). Available: http://www.npwrc.usgs.gov/resource/plants/vascplnt/vascplnt.htm [2006, February 11]. [22534]

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Description

Purple loosestrife is an erect perennial herb in the loosestrife family, with a square, woody stem and opposite or whorled leaves. Leaves are lance-shaped, stalkless, and heart-shaped or rounded at the base. Plants are usually covered by a downy pubescence. Loosestrife plants grow from four to ten feet high, depending upon conditions, and produce a showy display of magenta-colored flower spikes throughout much of the summer. Flowers have five to seven petals. Mature plants can have from 30 to 50 stems arising from a single rootstock.

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Description and Biology

  • Plant: erect perennial herb with a square, woody stem usually covered by downy hair; 4-10 ft. high, depending upon conditions.
  • Leaves: lance-shaped, stalk-less and rounded to heart-shaped at the base; arranged in pairs or whorls around the stem.
  • Flowers, fruits and seeds: produces a showy display of magenta-colored flower spikes throughout much of the summer. Individual flowers have five to seven petals. A single mature plant can have 30-50 stems arising from one rootstock, and can produce an estimated two to three million seeds per year. The flowering season extends from June to September; flowers require pollination by insects, for which they supply an abundant source of nectar.
  • Spreads: through the vast quantity of seeds, dispersed by wind and water. It also readily reproduces vegetatively through underground stems at a rate of about one foot per year.
  • Look-alikes: from a distance, purple loosestrife may be confused with blue vervain (Verbena hastata), blazing star (Liatris aspera and L. spicata), Canada germander (Teucrium canadense), swamp milkweed (Asclepias incarnata), and fireweed (Chamaenerion angustifolium), which is native to the northern U.S. and Canada.

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Diagnostic Description

At a distance, L. salicaria may be confused with Epilobium angustifolium, Verbena hastata, Teucrium canadense, or Liatris spp. Upon closer examination however, purple loosestrife is easily distinguished from these other magenta-flowered plants.

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Synonym

Lythrum anceps (Koehne) Makino; L. argyi H. Léveillé; L. intermedium Ledebour ex Colla; L. salicaria var. anceps Koehne; L. salicaria var. glabrum Ledebour; L. salicaria var. intermedium (Ledebour ex Colla) Koehne; L. salicaria var. mairei H. Léveillé.
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology

L. salicaria will occur in most wetland types from river margins and banks, to low-lying seasonally inundated areas in rough pasture, the margins of wet woodland and even seasonally pools.


Systems
  • Terrestrial
  • Freshwater
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Habitat characteristics

More info for the terms: phase, presence

Throughout its global distribution purple loosestrife is strongly linked with temperate climate and moist or saturated soils [129]. Unshaded, newly-exposed, moist soil appears most favorable for seedling establishment. Riverine habitats subjected to periodic but infrequent scouring, or lacustrine habitats subject to periodic water level reduction such as drought-exposed lakeshore or seasonal impoundment drawdown are good examples of habitats at risk of invasion. Once purple loosestrife seedlings become established, adults are quite flood tolerant [118]. Moisture is the most critical factor for growth and reproduction, but well-established plants can persist at dry sites for many years [21]. Keddy and Ellis [64] examined purple loosestrife seedling recruitment along a water level gradient, simulating conditions ranging from water levels 2 inches (5 cm) below the soil surface to standing water up to 4 inches (10 cm) above the soil surface. They found there was no significant (p = 0.44) effect of water depth on germination and early establishment of seedlings, indicating a broad tolerance for water level in the recruitment phase of purple loosestrife life history. Stream corridors with steep elevational gradients may be less susceptible to colonization by purple loosestrife due to gravitational constraints on seed dispersal [128].

Northern limits of purple loosestrife distribution may be strongly influenced by low growing season temperature. Under controlled conditions, growth was severely restricted at 46.4 degrees Fahrenheit (8 °C) compared with more "characteristic" growth at 64.4 degrees Fahrenheit (18°C) [113].

Purple loosestrife is found on both calcareous and acidic soils [111,113,129] and tolerates low-nutrient soils [111,117,141]. Typically found in open areas, purple loosestrife will tolerate some shade, but growth, reproduction and survival may be substantially reduced under shaded conditions [110,118].

Several characteristics of wetland or riparian habitats have been identified that may be predictive of invasibility by purple loosestrife. Assuming dispersal is largely via floating propagules, isolated wetland basins may be less susceptible to purple loosestrife colonization than areas with interconnected waterways. Additionally, narrow streams with steep gradients are probably less susceptible, because they are frequently scoured and contain fewer areas of slack water, while slower, broader flows are more likely to contain habitat suitable for colonization. Riparian areas that are mostly shaded are also less susceptible because purple loosestrife seedlings require relatively high light levels. Finally, the presence of one or more commonly associated taxa, such as cattails (Typha spp.), reed canarygrass (Phalaris arundinacea), sedges (Carex) spp., and rushes (Juncus spp.) may indicate a habitat that is highly susceptible to invasion by purple loosestrife [129].

  • 21. Blossey, Bernd; Schroeder, Dieter. 1995. Host specificity of three potential biological weed control agents attacking flowers and seeds of Lythrum salicaria (purple loosestrife). Biological Control. 5: 47-53. [37523]
  • 64. Keddy, Paul A.; Ellis, Timothy H. 1985. Seedling recruitment of 11 wetland plant species along a water level gradient: shared or distinct responses? Canadian Journal of Botany. 63(10): 1876-1879. [37503]
  • 110. Shamsi, S. R. A. 1976. Some effects of density and fertilizer on the growth and competition of Epilobium hirsutum and Lythrum salicaria. Pakistan Journal of Botany. 8(2): 213-220. [40265]
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 113. Shamsi, S. R. A.; Whitehead, F. 1977. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. IV. Effects of temperature and inter-specific competition and concluding discussion. Journal of Ecology. 65: 71-84. [39785]
  • 117. Shipley, Bill; Peters, Robert H. 1990. A test of the Tilman model of plant strategies: relative growth rate and biomass partitioning. The American Naturalist. 136(2): 139-153. [14502]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 128. Thompson, Daniel Q. 1989. Control of purple loosestrife. Fish and Wildlife Leaflet 13.4.11. Washington, DC: U.S. Department of Interior, Fish and Wildlife Service. 6 p. [18333]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 141. Whitehead, F. H. 1971. Comparative autecology as a guide to plant distribution. In: Duffey, E. O.; Watt, A. S., eds. The scientific management of animal and plant communities for conservation: Proceedings of the 11th symposium of the British Ecological Society; [Date unknown]; [Location unknown]. Oxford, England: Blackwell Scientific: 167-176. [40245]

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Key Plant Community Associations

Purple loosestrife is found across a variety of freshwater wetland
habitats in North America, and consequently is associated with a variety of
plant taxa, functional guilds and communities. Habitats where it is likely to be
found include: freshwater marshes [27,93,102,105,127,129], streambanks or lakeshores
[130],
floodplains [80,102,129],
seasonally-wet meadows/wet prairies [8,10,129], bogs [127], vernal ponds [58], openings in forested swamps
[63], intermittent streams [105], shallow impoundments, and ditches and canals
[102,105]. Purple loosestrife is listed by the U.S. Fish and
Wildlife Service Office of Biological Services as a typical broadleaf plant of
Palustrine Persistent Emergent Wetlands [94].


In a host-specificity test of potential biological
control agents for purple loosestrife, Blossey and Schroeder [21] included 13
plant species said to "occur in the same habitat" as purple
loosestrife and were "of wildlife importance." Although these species are not necessarily distributed
homogeneously or systematically across the North American
landscape, they likely represent a reasonable sample of typical plant
associates. These species were common cattail (Typha
latifolia), broadfruit bur-reed (Sparganium eurycarpum), broadleaf
arrowhead (Sagittaria latifolia), annual wildrice (Zizania aquatica),
Olney threesquare (Scirpus americanus), hardstem bulrush (Scirpus acutus), longhair sedge (Carex comosa), sandbar willow (Salix
exigua), curly dock (Rumex crispus), longroot smartweed (Polygonum
amphibium), lambsquarters (Chenopodium album), cursed buttercup (Ranunculus
sceleratus) and St. Anthony's turnip (Ranunculus bulbosus).

Classifications describing plant communities in which
purple loosestrife is a dominant species are:

New York [105]

Washington [58]

  • 8. Auclair, Allan N.; Bouchard, Andre; Pajaczkowski, Josephine. 1973. Plant composition and species relations on the Huntingdon Marsh, Quebec. Canadian Journal of Botany. 51: 1231-1247. [14498]
  • 10. Beauregard, N.; Leclair, R., Jr. 1988. Multivariate analysis of the summer habitat structure of Rana pipiens Schreber, in Lac Saint Pierre (Quebec, Canada). In: Szaro, Robert C.; Severson, Kieth E.; Patton, David R., technical coordinators. Management of amphibians, reptiles, and small mammals in North America: Proceedings of the symposium; 1988 July 19-21; Flagstaff, AZ. Gen. Tech. Rep. RM-166. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 129-143. [22679]
  • 21. Blossey, Bernd; Schroeder, Dieter. 1995. Host specificity of three potential biological weed control agents attacking flowers and seeds of Lythrum salicaria (purple loosestrife). Biological Control. 5: 47-53. [37523]
  • 27. Caldwell, Fredricka Ann; Crow, Garrett E. 1992. A floristic and vegetation analysis of a freshwater tidal marsh on the Merrimack River, West Newbury, Massachusetts. Rhodora. 94(877): 63-97. [18126]
  • 58. Huang, Chih-Lin; del Moral, Roger. 1988. Plant-environment relationships on the Montlake wildlife area, Seattle, Washington, USA. Vegetatio. 75: 103-113. [9742]
  • 63. Kearsley, Jennifer. 1999. Inventory and vegetation classification of floodplain forest communities in Massachusetts. Rhodora. 101(906): 105-135. [35963]
  • 80. Malecki, Richard A.; Rawinski, Thomas J. 1985. New methods for controlling purple loosestrife. New York Fish and Game Journal. 32(1): 9-19. [18331]
  • 93. Otto, Sibylle; Groffman, Peter M.; Findlay, Stuart E. G.; Arreola, Anna E. 1999. Invasive plant species and microbial processes in a tidal freshwater marsh. Journal of Environmental Quality. 28(4): 1252-1257. [37547]
  • 94. Patoine, A.; Pinel-Alloul, B.; Prepas, E. E. 2002. Effects of catchment perturbations by logging and wildfires on zooplankton species richness and composition in Boreal Shield lakes. Freshwater Biology. 47: 1996-2014. [3482]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 105. Reschke, Carol. 1990. Ecological communities of New York State. Latham, NY: New York State Department of Environmental Conservation, Natural Heritage Program. 96 p. [21441]
  • 127. Taft, John B.; Solecki, Mary Kay. 1990. Vascular flora of the wetland and prairie communities of Gavin Bog and Prairie Nature Preserve, Lake County, Illinois. Rhodora. 92(871): 142-165. [14522]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 130. Treberg, Michael A.; Husband, Brian C. 1999. Relationship between the abundance of Lythrum salicaria (purple loosestrife) and plant species richness along the Bar River, Canada. Wetlands. 19(1): 118-125. [37542]

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Habitat: Rangeland Cover Types

More info on this topic.

This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: cover, fresh, shrub, vine

SRM (RANGELAND) COVER TYPES [115]:

101 Bluebunch wheatgrass

102 Idaho fescue

103 Green fescue

104 Antelope bitterbrush-bluebunch wheatgrass

105 Antelope bitterbrush-Idaho fescue

106 Bluegrass scabland

107 Western juniper/big sagebrush/bluebunch wheatgrass

108 Alpine Idaho fescue

109 Ponderosa pine shrubland

110 Ponderosa pine-grassland

201 Blue oak woodland

202 Coast live oak woodland

203 Riparian woodland

204 North coastal shrub

205 Coastal sage shrub

206 Chamise chaparral

207 Scrub oak mixed chaparral

208 Ceanothus mixed chaparral

209 Montane shrubland

210 Bitterbrush

211 Creosote bush scrub

212 Blackbush

213 Alpine grassland

214 Coastal prairie

215 Valley grassland

216 Montane meadows

217 Wetlands

301 Bluebunch wheatgrass-blue grama

302 Bluebunch wheatgrass-Sandberg bluegrass

303 Bluebunch wheatgrass-western wheatgrass

304 Idaho fescue-bluebunch wheatgrass

305 Idaho fescue-Richardson needlegrass

306 Idaho fescue-slender wheatgrass

307 Idaho fescue-threadleaf sedge

308 Idaho fescue-tufted hairgrass

309 Idaho fescue-western wheatgrass

310 Needle-and-thread-blue grama

311 Rough fescue-bluebunch wheatgrass

312 Rough fescue-Idaho fescue

313 Tufted hairgrass-sedge

314 Big sagebrush-bluebunch wheatgrass

315 Big sagebrush-Idaho fescue

316 Big sagebrush-rough fescue

317 Bitterbrush-bluebunch wheatgrass

318 Bitterbrush-Idaho fescue

319 Bitterbrush-rough fescue

320 Black sagebrush-bluebunch wheatgrass

321 Black sagebrush-Idaho fescue

322 Curlleaf mountain-mahogany-bluebunch wheatgrass

323 Shrubby cinquefoil-rough fescue

324 Threetip sagebrush-Idaho fescue

401 Basin big sagebrush

402 Mountain big sagebrush

403 Wyoming big sagebrush

404 Threetip sagebrush

405 Black sagebrush

406 Low sagebrush

407 Stiff sagebrush

408 Other sagebrush types

409 Tall forb

410 Alpine rangeland

411 Aspen woodland

412 Juniper-pinyon woodland

413 Gambel oak

414 Salt desert shrub

415 Curlleaf mountain-mahogany

416 True mountain-mahogany

417 Littleleaf mountain-mahogany

418 Bigtooth maple

419 Bittercherry

420 Snowbrush

421 Chokecherry-serviceberry-rose

422 Riparian

501 Saltbush-greasewood

505 Grama-tobosa shrub

506 Creosotebush-bursage

507 Palo verde-cactus

508 Creosotebush-tarbush

601 Bluestem prairie

602 Bluestem-prairie sandreed

603 Prairie sandreed-needlegrass

604 Bluestem-grama prairie

605 Sandsage prairie

606 Wheatgrass-bluestem-needlegrass

607 Wheatgrass-needlegrass

608 Wheatgrass-grama-needlegrass

609 Wheatgrass-grama

610 Wheatgrass

611 Blue grama-buffalo grass

612 Sagebrush-grass

613 Fescue grassland

614 Crested wheatgrass

615 Wheatgrass-saltgrass-grama

701 Alkali sacaton-tobosagrass

702 Black grama-alkali sacaton

703 Black grama-sideoats grama

704 Blue grama-western wheatgrass

705 Blue grama-galleta

706 Blue grama-sideoats grama

707 Blue grama-sideoats grama-black grama

708 Bluestem-dropseed

709 Bluestem-grama

710 Bluestem prairie

711 Bluestem-sacahuista prairie

712 Galleta-alkali sacaton

713 Grama-muhly-threeawn

714 Grama-bluestem

715 Grama-buffalo grass

716 Grama-feathergrass

717 Little bluestem-Indiangrass-Texas wintergrass

718 Mesquite-grama

719 Mesquite-liveoak-seacoast bluestem

720 Sand bluestem-little bluestem (dunes)

721 Sand bluestem-little bluestem (plains)

722 Sand sagebrush-mixed prairie

723 Sea oats

724 Sideoats grama-New Mexico feathergrass-winterfat

725 Vine mesquite-alkali sacaton

726 Cordgrass

727 Mesquite-buffalo grass

728 Mesquite-granjeno-acacia

729 Mesquite

730 Sand shinnery oak

731 Cross timbers-Oklahoma

732 Cross timbers-Texas (little bluestem-post oak)

733 Juniper-oak

734 Mesquite-oak

735 Sideoats grama-sumac-juniper

801 Savanna

802 Missouri prairie

803 Missouri glades

804 Tall fescue

805 Riparian

807 Gulf Coast fresh marsh
  • 115. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. [23362]

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Habitat: Cover Types

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the terms: cover, swamp

SAF COVER TYPES [35]:

1 Jack pine

5 Balsam fir

12 Black spruce

13 Black spruce-tamarack

14 Northern pin oak

15 Red pine

16 Aspen

17 Pin cherry

18 Paper birch

19 Gray birch-red maple

20 White pine-northern red oak-red maple

21 Eastern white pine

22 White pine-hemlock

23 Eastern hemlock

24 Hemlock-yellow birch

25 Sugar maple-beech-yellow birch

26 Sugar maple-basswood

27 Sugar maple

28 Black cherry-maple

30 Red spruce-yellow birch

31 Red spruce-sugar maple-beech

32 Red spruce

33 Red spruce-balsam fir

34 Red spruce-Fraser fir

35 Paper birch-red spruce-balsam fir

37 Northern white-cedar

38 Tamarack

39 Black ash-American elm-red maple

40 Post oak-blackjack oak

42 Bur oak

43 Bear oak

44 Chestnut oak

45 Pitch pine

46 Eastern redcedar

50 Black locust

51 White pine-chestnut oak

52 White oak-black oak-northern red oak

53 White oak

55 Northern red oak

57 Yellow-poplar

58 Yellow-poplar-eastern hemlock

59 Yellow-poplar-white oak-northern red oak

60 Beech-sugar maple

61 River birch-sycamore

62 Silver maple-American elm

63 Cottonwood

64 Sassafras-persimmon

65 Pin oak-sweetgum

66 Ashe juniper-redberry (Pinchot) juniper

67 Mohrs (shin) oak

68 Mesquite

69 Sand pine

70 Longleaf pine

71 Longleaf pine-scrub oak

72 Southern scrub oak

73 Southern redcedar

74 Cabbage palmetto

75 Shortleaf pine

76 Shortleaf pine-oak

78 Virginia pine-oak

79 Virginia pine

80 Loblolly pine-shortleaf pine

81 Loblolly pine

82 Loblolly pine-hardwood

83 Longleaf pine-slash pine

84 Slash pine

85 Slash pine-hardwood

87 Sweetgum-yellow-poplar

88 Willow oak-water oak-diamondleaf (laurel) oak

89 Live oak

91 Swamp chestnut oak-cherrybark oak

92 Sweetgum-willow oak

93 Sugarberry-American elm-green ash

94 Sycamore-sweetgum-American elm

95 Black willow

96 Overcup oak-water hickory

97 Atlantic white-cedar

98 Pond pine

100 Pondcypress

101 Baldcypress

102 Baldcypress-tupelo

103 Water tupelo-swamp tupelo

104 Sweetbay-swamp tupelo-redbay

107 White spruce

108 Red maple

109 Hawthorn

110 Black oak

201 White spruce

202 White spruce-paper birch

203 Balsam poplar

204 Black spruce

205 Mountain hemlock

206 Engelmann spruce-subalpine fir

207 Red fir

208 Whitebark pine

209 Bristlecone pine

210 Interior Douglas-fir

211 White fir

212 Western larch

213 Grand fir

215 Western white pine

216 Blue spruce

217 Aspen

218 Lodgepole pine

219 Limber pine

220 Rocky Mountain juniper

221 Red alder

222 Black cottonwood-willow

223 Sitka spruce

224 Western hemlock

225 Western hemlock-Sitka spruce

226 Coastal true fir-hemlock

227 Western redcedar-western hemlock

228 Western redcedar

229 Pacific Douglas-fir

230 Douglas-fir-western hemlock

231 Port-Orford-cedar

232 Redwood

233 Oregon white oak

234 Douglas-fir-tanoak-Pacific madrone

235 Cottonwood-willow

236 Bur oak

237 Interior ponderosa pine

238 Western juniper

239 Pinyon-juniper

242 Mesquite

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

247 Jeffrey pine

248 Knobcone pine

249 Canyon live oak

250 Blue oak-foothills pine

251 White spruce-aspen

252 Paper birch

253 Black spruce-white spruce

254 Black spruce-paper birch

255 California coast live oak

256 California mixed subalpine
  • 35. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]

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Habitat: Plant Associations

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: bog, shrub

KUCHLER [70] PLANT ASSOCIATIONS:

K001 Spruce-cedar-hemlock forest

K002 Cedar-hemlock-Douglas-fir forest

K003 Silver fir-Douglas-fir forest

K004 Fir-hemlock forest

K005 Mixed conifer forest

K006 Redwood forest

K007 Red fir forest

K008 Lodgepole pine-subalpine forest

K009 Pine-cypress forest

K010 Ponderosa shrub forest

K011 Western ponderosa forest

K012 Douglas-fir forest

K013 Cedar-hemlock-pine forest

K014 Grand fir-Douglas-fir forest

K015 Western spruce-fir forest

K016 Eastern ponderosa forest

K017 Black Hills pine forest

K018 Pine-Douglas-fir forest

K020 Spruce-fir-Douglas-fir forest

K021 Southwestern spruce-fir forest

K022 Great Basin pine forest

K023 Juniper-pinyon woodland

K024 Juniper steppe woodland

K025 Alder-ash forest

K026 Oregon oakwoods

K028 Mosaic of K002 and K026

K029 California mixed evergreen forest

K030 California oakwoods

K031 Oak-juniper woodland

K032 Transition between K031 and K037

K033 Chaparral

K034 Montane chaparral

K035 Coastal sagebrush

K036 Mosaic of K030 and K035

K037 Mountain-mahogany-oak scrub

K038 Great Basin sagebrush

K039 Blackbrush

K040 Saltbush-greasewood

K041 Creosote bush

K042 Creosote bush-bur sage

K043 Paloverde-cactus shrub

K045 Ceniza shrub

K046 Desert: vegetation largely lacking

K047 Fescue-oatgrass

K048 California steppe

K049 Tule marshes

K050 Fescue-wheatgrass

K051 Wheatgrass-bluegrass

K052 Alpine meadows and barren

K054 Grama-tobosa prairie

K055 Sagebrush steppe

K056 Wheatgrass-needlegrass shrubsteppe

K057 Galleta-threeawn shrubsteppe

K059 Trans-Pecos shrub savanna

K060 Mesquite savanna

K061 Mesquite-acacia savanna

K062 Mesquite-live oak savanna

K063 Foothills prairie

K064 Grama-needlegrass-wheatgrass

K065 Grama-buffalo grass

K066 Wheatgrass-needlegrass

K067 Wheatgrass-bluestem-needlegrass

K068 Wheatgrass-grama-buffalo grass

K069 Bluestem-grama prairie

K070 Sandsage-bluestem prairie

K071 Shinnery

K072 Sea oats prairie

K073 Northern cordgrass prairie

K074 Bluestem prairie

K075 Nebraska Sandhills prairie

K076 Blackland prairie

K077 Bluestem-sacahuista prairie

K078 Southern cordgrass prairie

K081 Oak savanna

K082 Mosaic of K074 and K100

K083 Cedar glades

K084 Cross Timbers

K085 Mesquite-buffalo grass

K086 Juniper-oak savanna

K087 Mesquite-oak savanna

K088 Fayette prairie

K089 Black Belt

K090 Live oak-sea oats

K093 Great Lakes spruce-fir forest

K094 Conifer bog

K095 Great Lakes pine forest

K096 Northeastern spruce-fir forest

K097 Southeastern spruce-fir forest

K098 Northern floodplain forest

K099 Maple-basswood forest

K100 Oak-hickory forest

K101 Elm-ash forest

K102 Beech-maple forest

K103 Mixed mesophytic forest

K104 Appalachian oak forest

K106 Northern hardwoods

K107 Northern hardwoods-fir forest

K108 Northern hardwoods-spruce forest

K109 Transition between K104 and K106

K110 Northeastern oak-pine forest

K111 Oak-hickory-pine

K112 Southern mixed forest

K113 Southern floodplain forest

K114 Pocosin
  • 70. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. [3455]

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Habitat: Ecosystem

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [40]:

FRES10 White-red-jack pine

FRES11 Spruce-fir

FRES12 Longleaf-slash pine

FRES13 Loblolly-shortleaf pine

FRES14 Oak-pine

FRES15 Oak-hickory

FRES16 Oak-gum-cypress

FRES17 Elm-ash-cottonwood

FRES18 Maple-beech-birch

FRES19 Aspen-birch

FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES22 Western white pine

FRES23 Fir-spruce

FRES24 Hemlock-Sitka spruce

FRES25 Larch

FRES26 Lodgepole pine

FRES27 Redwood

FRES28 Western hardwoods

FRES29 Sagebrush

FRES30 Desert shrub

FRES31 Shinnery

FRES32 Texas savanna

FRES33 Southwestern shrubsteppe

FRES34 Chaparral-mountain shrub

FRES35 Pinyon-juniper

FRES36 Mountain grasslands

FRES37 Mountain meadows

FRES38 Plains grasslands

FRES39 Prairie

FRES40 Desert grasslands

FRES41 Wet Grasslands

FRES42 Annual grasslands

FRES44 Alpine
  • 40. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998]

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Habitat in the United States

Purple loosestrife is capable of invading many wetland types, including freshwater wet meadows, tidal and non-tidal marshes, river and stream banks, pond edges, reservoirs, and ditches.

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U.S. National Park Service Weeds Gone Wild website

Source: U.S. National Park Service

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Habitat & Distribution

Damp grasslands, banks. Almost throughout China [widespread in northern latitudes worldwide, Afghanistan, India, Japan, Korea, Mongolia, E Russia; N Africa, Europe, North America].
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© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

Source: Missouri Botanical Garden

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Comments: L. salicaria is native to Eurasia and was first reported from the northeastern coast of North America in 1814, (Stuckey 1980). Although purple loosestrife occurs in nearly all sections of the United States, the heaviest concentrations are in the glaciated wetlands of the northeast. Occurrences west of the Mississippi River appear to be scattered (Stuckey 1980), with the species establishing in reclamation projects in the west (Thompson and Jackson 1982).

Purple loosestrife is found in wetlands such as cattail marshes, sedge meadows, and open bogs. L. salicaria also occurs along stream and river banks and lake shores. In addition, the plant is found in ditches and other disturbed wet soil areas.

L. salicaria grows best in high organic soils, but tolerates a wide range of soils including clay, sand, muck, and silt (Thompson and Jackson 1982). Generally, the plant is found in full sun, but it can survive in 50% shade (Thompson and Jackson 1982). Typical associates include Typha latifolia, T. glauca, Phragmites australis, Spartina sp., Scirpus spp., and Carex spp. (Thompson and Jackson 1982).

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© NatureServe

Source: NatureServe

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Associations

Faunal Associations

The flowers attract long-tongued bees and butterflies, including Bombus spp. (Bumblebees) and the butterfly Pieris rapae (Cabbage White). The seeds are too small to be of any interest to birds, and it is unclear to what extent mammalian herbivores feed on the foliage. There have been attempts recently to release leaf beetles from Europe as a biocontrol measure. This species probably provides cover to some wetland species of birds because of its tall dense vegetation. Photographic Location
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© John Hilty

Source: Illinois Wildflowers

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Foodplant / open feeder
imago of Altica lythri grazes on leaf of Lythrum salicaria

Foodplant / open feeder
imago of Altica palustris grazes on leaf of Lythrum salicaria

Foodplant / open feeder
larva of Ametastegia equiseti grazes on leaf of Lythrum salicaria
Other: major host/prey

Foodplant / open feeder
imago of Aphthona lutescens grazes on leaf of Lythrum salicaria
Other: sole host/prey

In Great Britain and/or Ireland:
Foodplant / saprobe
effuse colony of Coremiella dematiaceous anamorph of Coremiella cubispora is saprobic on dead stem of Lythrum salicaria
Remarks: season: 7-10
Other: major host/prey

Foodplant / parasite
Erysiphe lythri parasitises Lythrum salicaria

Foodplant / open feeder
imago of Galerucella calmariensis grazes on leaf of Lythrum salicaria

Foodplant / open feeder
imago of Galerucella pusilla grazes on leaf of Lythrum salicaria

Foodplant / internal feeder
larva of Hylobius transversovittatus feeds within rootstock (woody) of Lythrum salicaria
Other: sole host/prey

Foodplant / saprobe
apothecium of Lachnum salicariae is saprobic on dead stem (base) of Lythrum salicaria

Foodplant / open feeder
imago of Lythraria salicariae grazes on leaf of Lythrum salicaria

Foodplant / internal feeder
larva of Nanophyes marmoratus feeds within ovules of Lythrum salicaria
Other: sole host/prey

Foodplant / feeds on
larva of Phytobius comari feeds on Lythrum salicaria

Foodplant / open feeder
imago of Psylliodes picina grazes on leaf of Lythrum salicaria

Foodplant / spot causer
epiphyllous, punctiform pycnidium of Septoria coelomycetous anamorph of Septoria brissaceana causes spots on live leaf of Lythrum salicaria
Remarks: season: 7-9

Foodplant / saprobe
fruitbody of Sistotrema octosporum is saprobic on dead, decayed stem of Lythrum salicaria
Other: minor host/prey

Foodplant / parasite
hypophyllous colony of Stenella dematiaceous anamorph of Stenella lythri parasitises dying leaf of Lythrum salicaria

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General Ecology

Purple loosestrife begins to bloom in July and continues until September or October. The flowers are pollinated by several different types of bees from the Megachilinae, Apinae, Xylopinae, and Bombinae; and by several butterflies: Pieris rapae, Colias philodice, and Cercyonis pegala (Balogh 1985). Seed production is prolific. There is an average of 120 seeds per capsule and up to 900 capsules per plant (Rawinski 1982). The lowest capsules on the stem are dehiscing while the upper stem capsules are still green.

The seeds are small, weighing 0.06 mg each (Shamsi and Whitehead 1974). Dispersal is mainly by wind, but seeds can also be transported on the feet of waterfowl or other wetland animals. Red-winged blackbirds have been observed eating the seeds (Rawinski 1982). Humans carry seeds inadvertently on clothing and shoes and in some instances, bee-keepers have purposely sown seeds in headwaters and wetlands to provide a steady source of nectar for their bees. The seeds and cotyledon stage seedlings are buoyant and can be dispersed by water currents (Balogh 1985). The seed bank potential for L. salicaria is enhanced by the high viability of the seeds. Viability decreased from 99% to 80% after two years of storage in a natural body of water (Rawinski 1982).

Seeds of L. salicaria can germinate in acidic or alkaline soils; in soils that are nutrient rich or nutrient poor. Light requirements for germination are minimal (Shamsi and Whitehead 1974). Temperature at the soil surface is a critical factor for germination. Seeds will germinate at temperatures ranging from 15 to 20 degrees C (Balogh 1985). Seeds germinate in high densities--about 10,000 to 20,000/sq. meter (Rawinski 1982). The interval between germination and flowering is eight to ten weeks (Rawinski 1982).

Seedlings that germinate in the spring grow rapidly and will produce a floral shoot up to 30 cm in length the first year. Summer-germinated seedlings develop only five or six pairs of leaves before the end of the growing season (Shamsi and Whitehead 1974). Spring-germinated seedlings have a higher survival rate than summer-germinated seedlings. Open grown shoots have a greater reproductive output than shoots growing in dense stands (Rawinski 1982). Once established, seedlings can survive shallow flooding of up to 30-45 cm in depth (Thompson and Stuckey 1980.).

The taproot is strongly developed in the seedling stage and persists throughout the life of the plant (Shamsi and Whitehead 1974). In mature plants, the taproot and major root branches become thick and woody (Rawinski 1982). The semi-woody aerial shoots die in the fall but persist for one to two years making stands of L. salicaria very dense. New shoots arise the following spring from buds at the top of the rootstocks (Rawinski 1982).

The rootstock is the main organ of perennation and vegetative spread is therefore limited (Shamsi and Whitehead 1974). L. salicaria can spread vegetatively by resprouting from cut stems and regenerating from pieces of root stock (Rawinski 1982).

Infestations of purple loosestrife appear to follow a pattern of establishment, maintenance at low numbers, and then dramatic population increases when conditions are optimal. L. salicaria flourishes in wetland habitats that have been disturbed or degraded from draining, natural drawdown in dry years, bulldozing, siltation, shore manipulation, cattle trampling, or dredging. Mudflats exposed following drawdowns will be quickly colonized if a loosestrife seed source is present. Seeds are usually present in such large numbers and germinate in such high densities that growth of native seedlings is suppressed (Rawinski 1982). Loosestrife crowds or shades out native species and eventually becomes a virtually monospecific stand.

L. salicaria is an extremely successful invader of wetlands that have been subjected to some type of disturbance: drawdown, siltation, drainage, ditching. Expansion in a wetland can be extensive and sudden due to the abundance of seeds produced and the rapid growth of seedlings. High seed viability and prolific seed production can build up a seed bank of massive proportions.

Purple loosestrife seed germinates in such high densities that it outcompetes native seedlings. The buildup of debris around the roots enable loosestrife to invade deeper water and to form dense stands that shade out other emergents and push out floating vegetation by closing open water spaces.

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Plant Response to Fire

More info for the term: root crown

Although no direct evidence exists, it is likely that purple loosestrife will survive fire by sprouting from buds located below the soil surface on the root crown [46,111].
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 46. Haber, Erich. 2001. Invasive plant data summary and control options: Purple loosestrife. In: Invasive plants of Canada: Guide to species and methods of control, [Online]. Available: http://www.magi.com/%%7Eehaber/lyth_sal.html [2002, January 25]. [40051]

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Broad-scale Impacts of Fire

More info for the term: fuel

Reports of interactions between purple loosestrife and fire usually attest to the difficulty associated with trying to burn plants as a control method. Such attempts are commonly described as being confounded by moist soil conditions and patchy fuel distribution [80,83,102,129]. Because postsenescent purple loosestrife retains persistent standing dead stem material [14], it is possible that dry winter or early spring conditions may permit dense stands to carry fire, but this is speculative.
  • 14. Benefield, Carri. 2000. Lythrum salicaria L. In: Bossard, Carla C.; Randall, John M.; Hoshovsky, Marc C., eds. Invasive plants of California's wildlands. Berkeley, CA: University of California Press: 236-240. [38336]
  • 80. Malecki, Richard A.; Rawinski, Thomas J. 1985. New methods for controlling purple loosestrife. New York Fish and Game Journal. 32(1): 9-19. [18331]
  • 83. McKeon, W. H. 1959. A preliminary report on the use of chemical herbicides to control purple loosestrife (Lythrum salicaria) on a small river. Proceedings, Northeast Weed Control Conference. 13: 329-332. [40097]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]

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Immediate Effect of Fire

More info for the term: root crown

Information describing the effect of fire on purple loosestrife is sparse, but several authors suggest that it does not burn well [83,129]. In a review, Haber [46] suggest that "fires generally do not burn at high enough temperatures to kill the root crown, especially in damp soils." Rawinski [102] indicated that individual plants will burn, but conditions that permit a fire to carry through purple loosestrife stands are probably not common.
  • 83. McKeon, W. H. 1959. A preliminary report on the use of chemical herbicides to control purple loosestrife (Lythrum salicaria) on a small river. Proceedings, Northeast Weed Control Conference. 13: 329-332. [40097]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 46. Haber, Erich. 2001. Invasive plant data summary and control options: Purple loosestrife. In: Invasive plants of Canada: Guide to species and methods of control, [Online]. Available: http://www.magi.com/%%7Eehaber/lyth_sal.html [2002, January 25]. [40051]

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Fire Ecology

More info for the terms: fire frequency, frequency, root crown, severity, shrub

Fire adaptations: Purple loosestrife is an herbaceous perennial, with growing points that overwinter on the root crown about 0.8 inches (2 cm) below the soil surface (see Botanical and Ecological Characteristics) [129]. FIRE REGIMES: Because purple loosestrife is distributed across many habitats in North America (see Distribution and Occurrence), FIRE REGIMES associated with the species vary. Recurrence and behavior of fire in areas where purple loosestrife occurs is likely to be closely tied to particular local FIRE REGIMES, and cannot be easily summarized over broad spatial scales. Given purple loosestrife's moisture requirements, it is unlikely to occur in areas experiencing frequently recurring fire. Similar to many areas that experience fire infrequently, occurrence of fire in areas where purple loosestrife is found is likely to driven by drought. However, information describing interactions between purple loosestrife and fire are lacking, and information linking purple loosestrife to specific North American FIRE REGIMES is nonexistent.

Given the dearth of information on fire and purple loosestrife and our relatively poor understanding of how purple loosestrife generally affects plant community dynamics where it occurs, any description of interactions between particular FIRE REGIMES and purple loosestrife is speculative. Where purple loosestrife displaces native vegetation dependent upon recurring fire for maintenance of a seral stage, persistent stands of invasive purple loosestrife may alter FIRE REGIMES if purple loosestrife burns less frequently or less readily than the native vegetation it displaces. For example, sedge meadow communities along the St. Lawrence River in southern Quebec where purple loosestrife is sometimes found, are historically maintained by dormant season fire recurring every 1 to 3 years. If invading purple loosestrife reduces fire frequency or severity at these sites, these communities are likely to succeed to woody species such as willow (Salix spp.) or maple (Acer spp.) [8].

The following table lists fire return intervals for communities or ecosystems throughout North America where purple loosestrife may occur. This list is not intended as a description of purple loosestrife distribution, but rather as a guide to FIRE REGIMES in areas where purple loosestrife could potentially be found. (For more specific distributional information see Distribution and Occurrence). While this list mainly describes upland habitats, purple loosestrife is generally associated with wetland or riparian habitats within these communities or ecosystems. As such, this list is meant as a guideline to illustrate historic FIRE REGIMES and is not to be interpreted as a strict description of FIRE REGIMES for purple loosestrife.

Community or Ecosystem Dominant Species Fire Return Interval Range (years)
silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii > 200 
grand fir Abies grandis 35-200 [5]
maple-beech-birch Acer-Fagus-Betula > 1000 
silver maple-American elm Acer saccharinum-Ulmus americana
sugar maple Acer saccharum > 1000 
sugar maple-basswood Acer saccharum-Tilia americana > 1000 [135]
California chaparral Adenostoma and/or Arctostaphylos spp. 95]
bluestem prairie Andropogon gerardii var. gerardii-Schizachyrium scoparium 69,95]
Nebraska sandhills prairie Andropogon gerardii var. paucipilus-Schizachyrium scoparium
bluestem-Sacahuista prairie Andropogon littoralis-Spartina spartinae
sagebrush steppe Artemisia tridentata/Pseudoroegneria spicata 20-70 
basin big sagebrush Artemisia tridentata var. tridentata 12-43 [108]
mountain big sagebrush Artemisia tridentata var. vaseyana 15-40 [6,25,85]
Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (40**) [133,143]
coastal sagebrush Artemisia californica
saltbush-greasewood Atriplex confertifolia-Sarcobatus vermiculatus
desert grasslands Bouteloua eriopoda and/or Pleuraphis mutica 5-100 
plains grasslands Bouteloua spp.
blue grama-needle-and-thread grass-western wheatgrass Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii
blue grama-buffalo grass Bouteloua gracilis-Buchloe dactyloides
cheatgrass Bromus tectorum
California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [95]
sugarberry-America elm-green ash Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica 135]
paloverde-cactus shrub Cercidium microphyllum/Opuntia spp. 95]
curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1000 [7,109]
mountain-mahogany-Gambel oak scrub Cercocarpus ledifolius-Quercus gambelii 95]
Atlantic white-cedar Chamaecyparis thyoides 35 to > 200 [135]
blackbrush Coleogyne ramosissima
northern cordgrass prairie Distichlis spicata-Spartina spp. 1-3 [95]
beech-sugar maple Fagus spp.-Acer saccharum > 1000 [135]
California steppe Festuca-Danthonia spp. 95]
black ash Fraxinus nigra 135]
juniper-oak savanna Juniperus ashei-Quercus virginiana
Ashe juniper Juniperus ashei
western juniper Juniperus occidentalis 20-70 
Rocky Mountain juniper Juniperus scopulorum
cedar glades Juniperus virginiana 3-7 
tamarack Larix laricina 35-200 [95]
western larch Larix occidentalis 25-100 [5]
creosotebush Larrea tridentata
Ceniza shrub Larrea tridentata-Leucophyllum frutescens-Prosopis glandulosa 95]
yellow-poplar Liriodendron tulipifera 135]
melaleuca Melaleuca quinquenervia 88]
wheatgrass plains grasslands Pascopyrum smithii 95]
Great Lakes spruce-fir Picea-Abies spp. 35 to > 200 
northeastern spruce-fir Picea-Abies spp. 35-200 [33]
southeastern spruce-fir Picea-Abies spp. 35 to > 200 [135]
Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to > 200 [5]
black spruce Picea mariana 35-200 
conifer bog* Picea mariana-Larix laricina 35-200 [33]
blue spruce* Picea pungens 35-200 [5]
red spruce* P. rubens 35-200 [33]
pine-cypress forest Pinus-Cupressus spp. 5]
pinyon-juniper Pinus-Juniperus spp. 95]
whitebark pine* Pinus albicaulis 50-200 [5]
jack pine Pinus banksiana 33]
Mexican pinyon Pinus cembroides 20-70 [86,126]
Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-300+ [4,5,107]
Sierra lodgepole pine* Pinus contorta var. murrayana 35-200 [5]
shortleaf pine Pinus echinata 2-15 
shortleaf pine-oak Pinus echinata-Quercus spp. 135]
Colorado pinyon Pinus edulis 10-49 [95]
slash pine Pinus elliottii 3-8 
slash pine-hardwood Pinus elliottii-variable
sand pine Pinus elliottii var. elliottii 25-45 [135]
South Florida slash pine Pinus elliottii var. densa 1-5 [88,135]
Jeffrey pine Pinus jeffreyi 5-30 
western white pine* Pinus monticola 50-200 
Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 
interior ponderosa pine* Pinus ponderosa var. scopulorum 2-10 [5]
Table Mountain pine Pinus pungens 135]
red pine (Great Lakes region) Pinus resinosa 10-200 (10**) [33,37]
red-white-jack pine* Pinus resinosa-P. strobus-P. banksiana 10-300 [33,54]
pitch pine Pinus rigida 6-25 [24,55]
pocosin Pinus serotina 3-8 
pond pine Pinus serotina 3-8 
eastern white pine Pinus strobus 35-200 
eastern white pine-eastern hemlock Pinus strobus-Tsuga canadensis 35-200 
eastern white pine-northern red oak-red maple Pinus strobus-Quercus rubra-Acer rubrum 35-200 
loblolly pine Pinus taeda 3-8 
loblolly-shortleaf pine Pinus taeda-P. echinata 10 to
Virginia pine Pinus virginiana 10 to
Virginia pine-oak Pinus virginiana-Quercus spp. 10 to
sycamore-sweetgum-American elm Platanus occidentalis-Liquidambar styraciflua-Ulmus americana 135]
galleta-threeawn shrubsteppe Pleuraphis jamesii-Aristida purpurea
eastern cottonwood Populus deltoides 95]
aspen-birch Populus tremuloides-Betula papyrifera 35-200 [33,135]
quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [5,45,84]
mesquite Prosopis glandulosa
mesquite-buffalo grass Prosopis glandulosa-Buchloe dactyloides
Texas savanna Prosopis glandulosa var. glandulosa 95]
black cherry-sugar maple Prunus serotina-Acer saccharum > 1000 [135]
mountain grasslands Pseudoroegneria spicata 3-40 (10**) [4,5]
Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [5]
coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [5,87,106]
California mixed evergreen Pseudotsuga menziesii var. m.-Lithocarpus densiflorus-Arbutus menziesii
California oakwoods Quercus spp. 5]
oak-hickory Quercus-Carya spp. 135]
oak-juniper woodland (Southwest) Quercus-Juniperus spp. 95]
northeastern oak-pine Quercus-Pinus spp. 10 to 135]
oak-gum-cypress Quercus-Nyssa-spp.-Taxodium distichum 35 to > 200 [88]
southeastern oak-pine Quercus-Pinus spp. 135]
coast live oak Quercus agrifolia 5]
white oak-black oak-northern red oak Quercus alba-Q. velutina-Q. rubra 135]
canyon live oak Quercus chrysolepis
blue oak-foothills pine Quercus douglasii-Pinus sabiana 5]
northern pin oak Quercus ellipsoidalis 135]
Oregon white oak Quercus garryana 5]
bear oak Quercus ilicifolia 135]
California black oak Quercus kelloggii 5-30 [95]
bur oak Quercus macrocarpa 135]
oak savanna Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium 2-14 [95,135]
shinnery Quercus mohriana 95]
chestnut oak Q. prinus 3-8 
northern red oak Quercus rubra 10 to
post oak-blackjack oak Quercus stellata-Q. marilandica
black oak Quercus velutina
live oak Quercus virginiana 10 to135]
interior live oak Quercus wislizenii 5]
cabbage palmetto-slash pine Sabal palmetto-Pinus elliottii 88,135]
blackland prairie Schizachyrium scoparium-Nassella leucotricha
Fayette prairie Schizachyrium scoparium-Buchloe dactyloides
little bluestem-grama prairie Schizachyrium scoparium-Bouteloua spp.
tule marshes Scirpus and/or Typha spp. 95]
redwood Sequoia sempervirens 5-200 [5,36,124]
southern cordgrass prairie Spartina alterniflora 1-3 [95]
baldcypress Taxodium distichum var. distichum 100 to > 300 
pondcypress Taxodium distichum var. nutans 88]
western redcedar-western hemlock Thuja plicata-Tsuga heterophylla > 200 [5]
eastern hemlock-yellow birch Tsuga canadensis-Betula alleghaniensis > 200 [135]
western hemlock-Sitka spruce Tsuga heterophylla-Picea sitchensis > 200 
mountain hemlock* Tsuga mertensiana 35 to > 200 [5]
elm-ash-cottonwood Ulmus-Fraxinus-Populus spp. 33,135]
*fire return interval varies widely; trends in variation are noted in the species summary
**mean
  • 4. Arno, Stephen F. 1980. Forest fire history in the Northern Rockies. Journal of Forestry. 78(8): 460-465. [11990]
  • 24. Buchholz, Kenneth; Good, Ralph E. 1982. Density, age structure, biomass and net annual aboveground productivity of dwarfed Pinus rigida Moll. from the New Jersey Pine Barren Plains. Bulletin of the Torrey Botanical Club. 109(1): 24-34. [8639]
  • 5. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. [36984]
  • 6. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. [342]
  • 7. Arno, Stephen F.; Wilson, Andrew E. 1986. Dating past fires in curlleaf mountain-mahogany communities. Journal of Range Management. 39(3): 241-243. [350]
  • 45. Gruell, G. E.; Loope, L. L. 1974. Relationships among aspen, fire, and ungulate browsing in Jackson Hole, Wyoming. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 33 p. In cooperation with: U.S. Department of the Interior, National Park Service, Rocky Mountain Region. [3862]
  • 85. Miller, Richard F.; Rose, Jeffery A. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. The Great Basin Naturalist. 55(1): 37-45. [25666]
  • 8. Auclair, Allan N.; Bouchard, Andre; Pajaczkowski, Josephine. 1973. Plant composition and species relations on the Huntingdon Marsh, Quebec. Canadian Journal of Botany. 51: 1231-1247. [14498]
  • 25. Burkhardt, Wayne J.; Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology. 57: 472-484. [565]
  • 33. Duchesne, Luc C.; Hawkes, Brad C. 2000. Fire in northern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 35-51. [36982]
  • 36. Finney, Mark A.; Martin, Robert E. 1989. Fire history in a Sequoia sempervirens forest at Salt Point State Park, California. Canadian Journal of Forest Research. 19: 1451-1457. [9845]
  • 37. Frissell, Sidney S., Jr. 1968. A fire chronology for Itasca State Park, Minnesota. Minnesota Forestry Research Notes No. 196. Minneapolis, MN: University of Minnesota. 2 p. [34527]
  • 54. Heinselman, Miron L. 1970. The natural role of fire in northern conifer forests. In: The role of fire in the Intermountain West: Symposium proceedings; 1970 October 27-29; Missoula, MT. Missoula, MT: Intermountain Fire Research Council: 30-41. In cooperation with: University of Montana, School of Forestry. [15735]
  • 84. Meinecke, E. P. 1929. Quaking aspen: A study in applied forest pathology. Tech. Bull. No. 155. Washington, DC: U.S. Department of Agriculture. 34 p. [26669]
  • 86. Moir, William H. 1982. A fire history of the High Chisos, Big Bend National Park, Texas. The Southwestern Naturalist. 27(1): 87-98. [5916]
  • 87. Morrison, Peter H.; Swanson, Frederick J. 1990. Fire history and pattern in a Cascade Range landscape. Gen. Tech. Rep. PNW-GTR-254. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 77 p. [13074]
  • 88. Myers, Ronald L. 2000. Fire in tropical and subtropical ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 161-173. [36985]
  • 95. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; Gottfried, Gerald J.; Haase, Sally M.; Harrington, Michael G.; Narog, Marcia G.; Sackett, Stephen S.; Wilson, Ruth C. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. [36978]
  • 106. Ripple, William J. 1994. Historic spatial patterns of old forests in western Oregon. Journal of Forestry. 92(11): 45-49. [33881]
  • 107. Romme, William H. 1982. Fire and landscape diversity in subalpine forests of Yellowstone National Park. Ecological Monographs. 52(2): 199-221. [9696]
  • 108. Sapsis, David B. 1990. Ecological effects of spring and fall prescribed burning on basin big sagebrush/Idaho fescue--bluebunch wheatgrass communities. Corvallis, OR: Oregon State University. 105 p. Thesis. [16579]
  • 109. Schultz, Brad W. 1987. Ecology of curlleaf mountain mahogany (Cercocarpus ledifolius) in western and central Nevada: population structure and dynamics. Reno, NV: University of Nevada. 111 p. Thesis. [7064]
  • 124. Stuart, John D. 1987. Fire history of an old-growth forest of Sequoia sempervirens (Taxodiaceae) forest in Humboldt Redwoods State Park, California. Madrono. 34(2): 128-141. [7277]
  • 126. Swetnam, Thomas W.; Baisan, Christopher H.; Caprio, Anthony C.; Brown, Peter M. 1992. Fire history in a Mexican oak-pine woodland and adjacent montane conifer gallery forest in southeastern Arizona. In: Ffolliott, Peter F.; Gottfried, Gerald J.; Bennett, Duane A.; Hernandez C., Victor Manuel; Ortega-Rubio, Alfred; Hamre, R. H., tech. coords. Ecology and management of oak and associated woodlands: perspectives in the southwestern United States and northern Mexico: Proceedings; 1992 April 27-30; Sierra Vista, AZ. Gen. Tech. Rep. RM-218. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 165-173. [19759]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 133. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. [19698]
  • 135. Wade, Dale D.; Brock, Brent L.; Brose, Patrick H.; Grace, James B.; Hoch, Greg A.; Patterson, William A., III. 2000. Fire in eastern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 53-96. [36983]
  • 143. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505. [2659]
  • 55. Hendrickson, William H. 1972. Perspective on fire and ecosystems in the United States. In: Fire in the environment: Symposium proceedings; 1972 May 1-5; Denver, CO. FS-276. [Washington, DC]: U.S. Department of Agriculture, Forest Service: 29-33. In cooperation with: Fire Services of Canada, Mexico, and the United States; Members of the Fire Management Study Group; North American Forestry Commission; FAO. [17276]

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Successional Status

More info on this topic.

More info for the terms: cohort, genet, marsh, natural, succession

The ways and extent to which purple loosestrife affects succession in wetland plant communities are not altogether clear. It is evident that purple loosestrife requires open, moist, bare substrate for establishment (see Site Characteristics and Regeneration Processes). It is generally agreed that purple loosestrife is a pioneer or gap-colonizing species that quickly responds to site disturbance by recruiting often-substantial numbers of new genets from a pre-existing seed bank [1,30,110].

Purple loosestrife displays many characteristics typical of pioneer species, such as rapid maturity, high seed production, tolerance of nutrient-poor environments, and high germination success. Yet North American populations, once established, also are potentially long-lived (22+ years), capable of growing to a relatively large size, and have shown the propensity for near-continuous, low-level recruitment in the absence of large-scale disturbance [1,129]. While evidence is somewhat limited, it is speculated natural mortality rates in adult plants are quite low [1].

Purple loosestrife, once established, can persist within a site for relatively long periods, even in the absence of frequent disturbance. After examining purple loosestrife population structure within several different communities in eastern Massachusetts, Anderson [1] concluded low levels of nearly-continuous recruitment are likely to occur in areas where mature plants (and the inevitable prodigious purple loosestrife seed bank) are present. Additionally, this trend is punctuated by occasional disturbances that provide conditions suitable for short-lived recruitment episodes in which relatively large cohorts of new plants are established.

But there is some question regarding the view that purple loosestrife inevitably dominates invaded sites in virtual monotypic stands. Anderson [2] points out that in a widely cited review by Thompson and others [129], estimates of the proportion of stand biomass attributed to purple loosestrife, which ostensibly increased over time following establishment, may instead have been attributable to increases in the number of stems per genet rather than greater numbers of individual plants. The number of annually produced stems per single genetically distinct plant has been shown to be a good predictor of the age of that individual [1]. Anderson [2] also notes observations described in Thompson and others [129] were strictly visual assessments, and since no hard data was collected, there is no way to definitively ascertain what, if any, changes in biomass distribution among species may have occurred.

In its native range, European populations of purple loosestrife may also form large monospecific stands following pregrowing season disturbance, but are prone to invasion by other species soon after stand establishment [110,111]. Whitehead [141] described the gradual yielding of monospecific stands of purple loosestrife to mixed species communities in England as being due to slow growth of purple loosestrife during periods of cool spring temperatures compared with competitors possessing low-temperature growth capabilities such as cattails or reeds (Phragmites spp.) It is likely that an aggregate of factors act to limit purple loosestrife site dominance in its native habitats [118].

Thompson and others [129] have reviewed several historical accounts of purple loosestrife stands, both in its native Europe and elsewhere. They determined that while purple loosestrife seldom maintains strong community dominance in native (European) habitats, it commonly forms dense, long-lasting, virtually monospecific stands in areas where it is not native, especially temperate North America. They considered 3 factors that could possibly account for this phenomenon: 1) the absence of many key insect predators that effectively reduce competitiveness of European purple loosestrife plants, 2) predominance of the muskrat in its native North American habitat and the impact of its selective Foraging behavior on cattails (see Importance to Livestock and Wildlife or Impacts and Control), and 3) the possibility that North American purple loosestrife may have evolved adaptive traits which make it more vigorous and competitive than its European relatives.

Many factors are likely to affect the ability of purple loosestrife to form and maintain extensive monodominant stands in North American wetlands. Characteristics particular to certain classes of habitat may lead to monodominance. Auclair and others [8] have noted some trends in 2 distinct plant communities of Huntington Marsh, located along the St. Lawrence River near the junction of the Quebec, Ontario and New York borders. In the emergent aquatic community, the dominant emergent taxa tended to exclude each other, resulting in a mosaic of nearly monospecific communities. In particular, river bulrush (Schoenoplectus fluviatilis), common reed (Phragmites australis) and narrow-leaved cattail (Typha angustifolia) displayed this phenomenon. In contrast, sedge meadow communities were much more diverse and lacked the dominance and segregation of species. Instead they demonstrated subtle gradients in composition that were generally difficult to discern.

The nature of particular disturbance events may also impact initial floristics and subsequent successional trajectories. For instance, the relative competitiveness of purple loosestrife seedlings following disturbance may depend upon when initiation of the new seedling community occurs within the growing season. Because purple loosestrife growth rates are closely linked to day length [112], early summer establishment of a seedling cohort or community, compared with late summer establishment, is more likely to result in a monospecific stand of purple loosestrife because purple loosestrife seedlings will be more competitive [102].

More research is needed to help elucidate the means and extent to which purple loosestrife alters successional trajectories and community dynamics. Long-term studies that examine preinvasion vs. postinvasion data would be particularly helpful.

  • 1. Anderson, Mark G. 1991. Population structure of Lythrum salicaria in relation to wetland community structure. Durham, NH: University of New Hampshire. 93 p. Thesis. [39754]
  • 2. Anderson, Mark G. 1995. Interactions between Lythrum salicaria and native organisms: a critical review. Environmental Management. 19(2): 225-231. [37517]
  • 8. Auclair, Allan N.; Bouchard, Andre; Pajaczkowski, Josephine. 1973. Plant composition and species relations on the Huntingdon Marsh, Quebec. Canadian Journal of Botany. 51: 1231-1247. [14498]
  • 30. Day, R. T.; Keddy, P. A.; McNeill, J.; Carleton, T. 1988. Fertility and disturbance gradients: a summary model for riverine marsh vegetation. Ecology. 69(4): 1044-1054. [39768]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 110. Shamsi, S. R. A. 1976. Some effects of density and fertilizer on the growth and competition of Epilobium hirsutum and Lythrum salicaria. Pakistan Journal of Botany. 8(2): 213-220. [40265]
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 112. Shamsi, S. R. A.; Whitehead, F. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. II. Growth and development in relation to light. Journal of Eocology. 62: 632-645. [39786]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 141. Whitehead, F. H. 1971. Comparative autecology as a guide to plant distribution. In: Duffey, E. O.; Watt, A. S., eds. The scientific management of animal and plant communities for conservation: Proceedings of the 11th symposium of the British Ecological Society; [Date unknown]; [Location unknown]. Oxford, England: Blackwell Scientific: 167-176. [40245]

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Regeneration Processes

More info for the terms: adventitious, cotyledon, density, rootstock

Breeding system: Purple loosestrife is a tristylous species (3 different style lengths), usually in a 1:1:1 ratio, indicating sexual reproduction is probably its most important means of regeneration [9]. It is primarily an outcrosser, as self-pollination in purple loosestrife is rare, and has been shown to reduce seed production [111].

Pollination: Purple loosestrife is insect pollinated. Most reports indicate honeybees are the main pollinators [43,73]. Others include bumblebees [72,73], leaf-cutter bees and carpenter bees [72], as well as a variety of butterflies [72,73]. Hummingbirds have been observed taking nectar from purple loosestrife in British Columbia [98], although pollination by hummingbirds is undocumented.

Seed production: Purple loosestrife produces an immense number of seeds. Estimates of seed production rates range from just over 100,000 seeds per plant for young plants with single stems [111], to over 2.5 million seeds per plant for established plants with an average of 30 stems per plant [129]. Although perennial, purple loosestrife is capable of producing viable seed during its 1st growing season [116]. Seed output is largely a function of plant age, size, and vigor [129]. Shoots growing in relatively dense stands tend to produce fewer and smaller inflorescences than those growing in more open areas [102].

Seed dispersal: Because seeds are small and light they are thought to be dispersed, at least in part, by wind [53,111]. However, Thompson and others [129] report observations that seedling densities decline sharply within a 33 foot (10 m) perimeter of the parent plant and seedlings are often distributed downslope from the parent plant rather than downwind, suggesting a limited role for wind dispersal. Dispersal via moving water is also likely [53,118,119]. Seeds and cotyledon stage seedlings are reportedly buoyant [9], although there are reports that purple loosestrife seeds don't float [119]. Floating seeds may disperse to suitable sites for establishment. Seeds that sink may germinate while submerged, then rise to the surface and drift to suitable sites for establishment [129]. Seeds may be transported in fur of mammals, plumage of waterfowl, mud attached to footgear, vehicle treads or cooling systems of outboard motors [53,128,129]. Thompson and others [129] also suggest birds may deposit ingested seeds in areas where wind or gravity-mediated dispersal seems unlikely.

Seed banking: Given its high seed output and ability to produce seed in its 1st growing season, purple loosestrife can establish substantial soil seed banks. Seeds may remain viable for at least 2 to 3 years [102,111], although the long-term viability of seeds stored in the soil seed bank remains under investigation [139]. Seeds may remain viable even when subjected to saturating conditions. Viability of seeds that were stored underwater was tested at 4-month intervals under ideal germination conditions. Germination declined from an initial rate of 99% to 93% after 1 year and 80% after 2 years [102].

Purple loosestrife has the potential to dominate the soil seed bank where it becomes well established. Soil samples taken from within purple loosestrife stands in emergent wetlands in southeastern Minnesota contained an average of 37,963 purple loosestrife seeds per ft2 (410,000 /m2) in the top 2 in (5 cm) of soil. Seeds were distributed within this entire profile and seed density increased with proximity to the soil surface. Under greenhouse conditions chosen to promote germination, and using soil samples from the above source spread 0.4 in (1 cm) deep, recruitment failed to exhaust the seed bank [138,140]. From the same experiment, purple loosestrife seedlings were found in 91% of untreated (no herbicide) 6.6 x 6.6 feet (2 x 2 m) quadrats, the most frequently encountered species in the soil seed bank [140].

Germination: Germination is greatest in unshaded, wet soils, with temperatures >68 degrees Fahrenheit (20º C) [20]. Shamsi and Whitehead [111] demonstrated germination is constrained at low temperatures between about 50 to 59 degrees Fahrenheit (10°-15° C), and no germination occurred below 57 degrees Fahrenheit (14° C). Experimental evidence indicates seed dormancy may be enforced by burial, with germination response decreasing linearly (p = 0.001, r2 = 0.89) from 90% at the soil surface to 0% at 0.8 in (2 cm), even under conditions known to promote germination in wetland plants [138]. Any disturbance that redistributes seeds to within the upper 0.8 inch (2 cm) of soil is likely to promote germination. Although light exposure is a prerequisite for germination, length of exposure does not appear important [112]. Purple loosestrife seeds are capable of germinating underwater [64].

Seedling establishment/growth: Favorable recruitment conditions are largely a function of disturbance that creates areas where little to no vegetation is present [99]. Estimates of maximum initial seedling density vary greatly, from 926 to 1,852 foot-2 (10,000-20,000 m-2) on bare open mudflats [102] to 2.8 to 4.6 foot-2 (30-50 m-2) in vegetated semiflooded wetlands. In areas where large numbers of seeds are present in the seed bank, small changes in area favorable for establishment can yield large fluctuations in recruitment [1].

In order to begin successful establishment, floating seeds or propagules must settle on moist soil [129]. Purple loosestrife can establish in soil beneath standing water [64].

Growth is limited by cold temperature and is considerably slowed at around 46 to 50 degrees Fahrenheit (8-10º C) [141]. Light availability can also limit growth and development. Under diminishing light intensities, vegetative growth is slowed, the numbers of flowers, fruits, and seeds per fruit are fewer, and the average dry weight of fruits declines, but there is no change in average dry weight of individual seeds [112]. Growth is also affected by day length. Shamsi and Whitehead [112] found leaf area and plant dry weight were significantly (P<0.05) reduced when plants were subjected to a 9-hour photoperiod compared with a 16-hour photoperiod. Plants in the 9-hour treatment grew in a comparatively flattened, semi-prostrate condition.

Asexual regeneration: The rootstock is the main organ of perennation, and unaided wide vegetative spread is unlikely. New shoots arise from buds at the top of the rootstock [111]. Root crowns expand annually to accommodate increasing numbers of shoots, but may reach maximum growth at around 20 inches (0.5 m) in diameter [129].

Purple loosestrife can consistently resprout in response to aboveground damage, often fairly rapidly. A greenhouse experiment showed 91% of clipped seedlings resprouted within 42 days [39]. Live stems that are dislodged and buried can give rise to new shoots via adventitious buds [23,129].

  • 1. Anderson, Mark G. 1991. Population structure of Lythrum salicaria in relation to wetland community structure. Durham, NH: University of New Hampshire. 93 p. Thesis. [39754]
  • 9. Balogh, Gregory Robert. 1986. Ecology, distribution, and control of purple loosestrife (Lythrum salicaria) in northwest Ohio. Columbus, OH: Ohio State University. 122 p. Thesis. [40074]
  • 20. Blossey, Bernd; Schat, Marjolein. 1997. Performance of Galerucella calmariensis (Coleoptera: Chrysomelidae) on different North American populations of purple loosestrife. Environmental Entomology. 26(2): 439-445. [37549]
  • 23. Brown, Beverly J.; Wickstrom, Conrad E. 1997. Adventitious root production and survival of purple loosestrife (Lythrum salicaria) shoot sections. Ohio Journal of Science. 97(1): 2-4. [37526]
  • 39. Gabor, T. Shane; Murkin, H. R. 1990. Effects of clipping purple loosestrife seedlings during a simulated wetland drawdown. Journal of Aquatic Plant Management. 28: 98-100. [40091]
  • 43. Grabas, Gregory P.; Laverty, Terence M. 1999. The effect of purple loosestrife (Lythrum salicaria L.; Lythraceae) on the pollination and reproductive success of sympatric co-flowering wetland plants. Ecoscience. 6(2): 230-242. [37534]
  • 53. Heidorn, Randy; Anderson, Brian. 1991. Vegetation management guideline: purple loosestrife (Lythrum salicaria L.). Natural Areas Journal. 11(3): 172-173. [15019]
  • 64. Keddy, Paul A.; Ellis, Timothy H. 1985. Seedling recruitment of 11 wetland plant species along a water level gradient: shared or distinct responses? Canadian Journal of Botany. 63(10): 1876-1879. [37503]
  • 72. Levin, Donald A. 1970. Assortative pollination in Lythrum. American Journal of Botany. 57(1): 1-5. [39787]
  • 73. Levin, Donald A.; Kerster, Harold W. 1973. Assortative pollination for stature in Lythrum salicaria. Evolution. 27: 144-152. [39778]
  • 98. Pojar, Jim. 1975. Hummingbird flowers of British Columbia. Syesis. 8: 25-28. [6537]
  • 99. Rachich, J.; Reader, R. J. 1999. An experimental study of wetland invasibility by purple loosestrife (Lythrum salicaria). Canadian Journal of Botany. 77(10): 1499-1503. [37552]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 111. Shamsi, S. R. A.; Whitehead, F. H. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. I. General biology, distribution and germination. Journal of Ecology. 62(79): 272-290. [18329]
  • 112. Shamsi, S. R. A.; Whitehead, F. 1974. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. II. Growth and development in relation to light. Journal of Eocology. 62: 632-645. [39786]
  • 116. Shipley, B.; Parent, M. 1991. Germination responses of 64 wetland species in relation to seed size, minimum time to reproduction and seedling relative growth rate. Functional Ecology. 5(1): 111-118. [14554]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 119. Skoglund, S. Jerry. 1990. Seed dispersing agents in two regularly flooded river sites. Canadian Journal of Botany. 68: 754-760. [11486]
  • 128. Thompson, Daniel Q. 1989. Control of purple loosestrife. Fish and Wildlife Leaflet 13.4.11. Washington, DC: U.S. Department of Interior, Fish and Wildlife Service. 6 p. [18333]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 138. Welling, Charles H.; Becker, Roger L. 1990. Seed bank dynamics of Lythrum salicaria L.: implications for control of this species in North America. Aquatic Botany. 38(2-3): 303-309. [17423]
  • 139. Welling, Charles H.; Becker, Roger L. 1992. Life history and taxonomic status of purple loosestrife in Minnesota: implications for management and regulation of this exotic plant. Special Publication 146. St. Paul, MN: Department of Natural Resources, Division of Fish and Wildlife. 15 p. [40255]
  • 140. Welling, Charles H.; Becker, Roger L. 1993. Reduction of purple loosestrife establishment in Minnesota wetlands. Wildlife Society Bulletin. 21(1): 56-64. [37502]
  • 141. Whitehead, F. H. 1971. Comparative autecology as a guide to plant distribution. In: Duffey, E. O.; Watt, A. S., eds. The scientific management of animal and plant communities for conservation: Proceedings of the 11th symposium of the British Ecological Society; [Date unknown]; [Location unknown]. Oxford, England: Blackwell Scientific: 167-176. [40245]

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Growth Form (according to Raunkiær Life-form classification)

More info on this topic.

More info for the terms: helophyte, hemicryptophyte

RAUNKIAER [100] LIFE FORM:
Hemicryptophyte
Helophyte
  • 100. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843]

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Life Form

More info for the term: forb

Forb

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Life History and Behavior

Cyclicity

Flower/Fruit

Fl. Per.: July-Sept.
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© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

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Reproduction

Biology and Spread

Purple loosestrife enjoys an extended flowering season, generally from June to September, which allows it to produce vast quantities of seed. The flowers require pollination by insects, for which it supplies an abundant source of nectar. A mature plant may have as many as thirty flowering stems capable of producing an estimated two to three million, minute seeds per year.

Purple loosestrife also readily reproduces vegetatively through underground stems at a rate of about one foot per year. Many new stems may emerge vegetatively from a single rootstock of the previous year. "Guaranteed sterile" cultivars of purple loosestrife are actually highly fertile and able to cross freely with purple loosestrife and with other native Lythrum species. Therefore, outside of its native range, purple loosestrife of any form should be avoided.

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U.S. National Park Service Weeds Gone Wild website

Source: U.S. National Park Service

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Molecular Biology and Genetics

Molecular Biology

Barcode data: Lythrum salicaria

The following is a representative barcode sequence, the centroid of all available sequences for this species.


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Source: Barcode of Life Data Systems (BOLD)

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Statistics of barcoding coverage: Lythrum salicaria

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 4
Specimens with Barcodes: 16
Species With Barcodes: 1
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© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2014

Assessor/s
Kavak, S.

Reviewer/s
Lansdown, R.V. & Smith, K.

Contributor/s
Lansdown, R.V., Rhazi, L., Rhazi, M. & Flanagan, D.

Justification
This species is classed as Least Concern as it is widespread with stable populations and does not face any major threats.
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National NatureServe Conservation Status

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

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NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

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As of this writing (2002), purple loosestrife is listed as a noxious weed in 29 states in the U.S. and 2 Canadian provinces. See the Invaders or Plants databases for current information. The state of Minnesota has prohibited the sale of European wand loosestrife and any cultivars from crosses between purple and European wand loosestrife [139].
  • 139. Welling, Charles H.; Becker, Roger L. 1992. Life history and taxonomic status of purple loosestrife in Minnesota: implications for management and regulation of this exotic plant. Special Publication 146. St. Paul, MN: Department of Natural Resources, Division of Fish and Wildlife. 15 p. [40255]

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Status

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status, and wetland indicator values.

Public Domain

USDA NRCS National Plant Data Center & Louisiana State University-Plant Biology; partial funding from the US Geological Survey and the US National Biological Information Infrastructure

Source: USDA NRCS PLANTS Database

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Population

Population

L. salicaria is widespread and abundant throughout its native range and is extremely abundant in parts of its introduced range.


Population Trend
Stable
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Threats

Major Threats
There are no major threats to this species.
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Management

Conservation Actions

Conservation Actions

There are no conservation measures in place or needed.

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Management Requirements: Once purple loosestrife becomes established in a wetland it displaces endemic vegetation through rapid growth and heavy seed production (Rawinski 1982). L. salicaria has a detrimental impact on native wetland vegetation and associated wildlife. Important wildlife food plants such as cattails and pondweed are displaced or shaded out as L. salicaria expands across a wetland. If purple loosestrife is left unchecked, the wetland eventually becomes a monoculture of loosestrife (Rawinski 1982). The invasion of L. salicaria leads to a loss of plant diversity, which also leads to a loss of wildlife diversity.

Management objectives may include eradicating populations, containing populations or preventing establishment. Monitoring should be used to track the accomplishment of these objectives.

The best time to search for purple loosestrife is in July and August when the plants are blooming. The bright magenta flowers are easy to spot at a great distance. Aerial surveys can be used to note the yearly position of large populations. An advancing or receding boundary would be identifiable from air photos. Ground surveys are more feasible for tracking small populations and finding newly established populations. Look for seedlings in June.

The following individuals are involved in public awareness campaigns or wetland surveys:

John Schwegman, Director, Botany Program, Illinois Dept. Conservation, Springfield, Illinois 62706.

Rich Henderson, Consultant, Natural Areas Management, 2845 Timberlane Verona, Wisconsin 53593.

Noel Cutright, Purple Loosestrife Task Force, 3352 Knollwood Rd., West Bend, Wisconsin 53095.

Purple loosestrife Survey-Nevin, Wisconsin Dept. Natural Resources, P.O. Box 7921, Madison, Wisconsin 53791.

Jay Rendall, Coordinator, Purple Loosestrife Program, Minnesota Dept. Natural Resources, Box 25, 500 Lafayette Rd., St. Paul, MN 55155.

Several control methods have been attempted with varying degrees of success. Natural area managers must determine their objectives first. Is it more feasible to contain or control populations of purple loosestrife? Large populations extending over three acres or more will be difficult if not impossible to completely eradicate using presently known methods. These large populations should be contained at their present position. Preventing the expansion can be accomplished through hand-pulling new plants along the periphery or spraying herbicide on plants extending beyond the main body of the population. Smaller populations can be controlled through eradication. Populations up to three acres can be cleared with herbicides or hand-pulled, depending upon the size of the work crew and time available.

CHEMICAL: The herbicide glyphosate is most commonly used to control L. salicaria. Glyphosate is available under the trade names RoundupTM and RodeoTM, manufactured by Monsanto. Roundup cannot be used over water. Another formulation of glyphosate known as Rodeo contains a non-ionic surfactant and has been approved for use over water. Ortho X-77 is the non-ionic surfactant recommended for use with Rodeo, but several other non-ionic surfactants were cleared for use with Rodeo in 1985 (Balogh 1985).

The major disadvantage in using Rodeo is that glyphosate is a non-specific systemic. Broadcast spraying of non-selective herbicides kills all of the vegetation and may result in an increase in loosestrife density because of seed germination following the removal of competing perennial vegetation (Minnesota DNR 1987). Spot application of Rodeo directly onto L. salicaria would ensure that no large holes would appear in the marsh vegetation and that competition would be unaffected. The safest method of applying glyphosate herbicide is to cut off all stems at about 6 inches and then paint or drip onto the cut surface a 20-30% solution (Henderson 1987).

Spraying should be done after the period of peak bloom, usually late August (Balogh 1985, Rawinski 1982). One to two percent solutions of Rodeo have been recommended as sufficient to kill L. salicaria (Henderson 1987, Minnesota DNR 1987, Balogh 1985, Thrune pers. comm.). Work done by Jim Reinartz at the U.W.-Milwaukee Field Station indicates it is best to spray no more than 25-50% of a plant's foliage (Henderson 1987). This will help protect against overspraying which might damage adjacent vegetation.

It is critical that any control effort be followed up the same growing season and for several years afterwards since some plants will be missed, new seedlings may sprout from the extensive seed bank, and a few plants will survive the low-dosage treatment (Henderson 1987, Minnesota DNR 1987). Higher dosage and careless application, however, inevitably kills more surrounding vegetation and leads to establishment of loosestrife seedlings (Minnesota DNR 1987).

For larger infestations where spot application of glyphosate is not practical, broadleaf herbicides can be used. They have the advantage of not harming monocot species, which are the dominants in most wetland types. Broadleaf herbicides (2,4-D based) can be effective on loosestrife if applied in late May or early June (Henderson 1987). The disadvantage of treating early in the season is that purple loosestrife plants are easily overlooked when not in flower. A combination of 2,4-D and dicamba has been used on a limited basis in western irrigation ditches (Jackson pers. comm.). The EPA has approved a 1:1 tank mix of these two products. Once L. salicaria has reached 10-15% of its mature growth, it can be sprayed with good results. To ensure complete coverage and compensate for spotty application, repeat the treatment once during the growing season (Jackson pers. comm.).

PULLING: Hand-removal is recommended for small populations and isolated stems. Ideally, the plants should be pulled out before they have set seed. The entire rootstock must be pulled out since regeneration from root fragments is possible. Be sure to minimize disturbances to the soil and native vegetative cover. Remove uprooted plants and broken stems from the area since the broken stems can resprout (Rawinski 1982).

REPLACEMENT: Replacement control has been attempted in several wildlife refuges (Balogh 1985, Rawinski 1982). Rawinski (1982) sowed Japanese millet (Echinochloa frumentacea) with L. salicaria and found that the millet seedlings outcompeted the loosestrife seedlings. The millet must be planted immediately after marsh drawdown has occurred. Balogh (1985) found that Japanese millet does not regenerate well and would have to be replanted every year. Balogh (1985) attempted a replacement treatment using native seed. Polygonum lapathifolium was seeded with purple loosestrife and the Polygonum outcompeted the loosestrife. However, the following spring L. salicaria would start growing first due to its overwintering rootstock. Replacement methods would have a very limited application within a natural area, but they may be useful to control or contain loosestrife populations on buffer property.

BIOLOGICAL: Several characteristics of L. salicaria make it an ideal candidate for biological control (USFWS 1987). Batra (et al. 1986) recommends detailed ecological and host-specificity studies for six European species: a cecidomyiid fly whose galling can reduce purple loosestrife foliage by 75% and seed production by 80%; a stem and root boring weevil; two chrysomelids that can cause nearly 50% defoliation; and two weevils that mine ovaries and seeds. The results of Batra et al. (1986) indicated that the chances of successful biological control of L. salicaria in North America are excellent.

The following individuals are familiar with L. salicaria and can suggest control strategies:

Dottie Thompson, Horicon National Wildlife Refuge, Rt. 2, Mayville, Wisconsin 53050. (414) 387-2658.

Rich Henderson, Consultant, Natural Area Management, 2845 Timberlane, Verona, Wisconsin 53593. (608) 845-7065.

John Schwegman, Director, Botany Program, Illinois Dept. Conservation, Springfield, Illinois 62706.

Tom Jackson, Leader, Field Research Station, U.S. Fish and Wildlife Service, P.O. Box 25007, Denver, Colorado 80225.

Jay Rendall, Coordinator, Purple Loosestrife Program, MN Dept of Natural Resources, Box 25, 500 Lafayette Rd, St. Paul, MN 55155.

Management Research Programs: A research project in Wisconsin includes investigations on different methods of control and different herbicide treatments. The ecology of L. salicaria including seed bank buildup is also under investigation. Contact: Rich Henderson, Consultant-Natural Area Management. 2845 Timberlane, Verona, Wisconsin 53593.

Hand cutting purple loosestrife and fertilizing cattails under varying degrees of wetness is being studied at Indiana Dunes National Lakeshore. Contact: Ron Heibert, Chief, Division of Science, 1100 N. Mineral Springs Rd., Porter, Indiana 46304.

Research on the effectiveness of various chemical controls will be conducted in Illinois, pending funding. Contact: John Schwegman, Director, Botany Program, Illinois Dept. Conservation, Springfield, Illinois 62706.

A research project funded by the Metropolitan Council (MN) is being conducted by Hennepin County Park Reserve. Chemical control techniques are to be evaluated for 2 years in control plots. Contact: Tom Hollenhorst, Hennepin County Park Reserve, 3800 Co. Rd. 24, Maple Plain, MN 55359.

The Minnesota Legislative Commission on Minnesota Resources (LMCR) has funded a comprehensive control program over a two year period. The program will inventory purple loosestrife in Minnesota, keep abreast of current contol methods and research, implement a prioritized control program, monitor environmental impact and effectiveness of control, promote public awareness campaigns, and coordinate agencies control efforts within the state. Contact: Jay Rendall, Coordinator, Purple Loosestrife Program, MN Dept of Natural Resources, Box 25, 500 Lafayette Rd, St. Paul, MN 55155.

Management Research Needs:

Biological control methods should be a priority for research. Repeated chemical treatments are costly and the long-term effects on natural systems are not fully understood. Preliminary investigations in Europe have revealed several host-specific insects that keep L. salicaria in check. Further research is warranted. Research is needed to assess the potential productivity of the seed bank. How extensive is the seed bank in a wetland in comparison to the size of the above-ground population? What is the rate of seed buildup? Can the age of a seed bank be determined? What is the viability of purple loosestrife seed? More research is needed on herbicide treatments that will give the most selective application with the least impact to the surrounding competitive vegetation, i.e. wick applications, etc. Available information suggests that research on mechanical treatments will not yield helpful results.

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Impacts and Control

More info for the terms: adventitious, association, bog, competition, cover, density, fire management, genet, invasive species, marsh, natural, presence, root crown, rootstock, swamp

Impacts:
Purple loosestrife can be highly competitive, often reported as occurring in dense, monospecific stands, with the potential to dominate wetland plant communities where it occurs (see Successional Status) [1,41,65,66,78,129,136,137]. While it is evident that invading purple loosestrife may have harmful impacts on native flora and fauna, more research is needed to clarify the extent of these impacts. Hager and McCoy [47] and Anderson [2] provide critical reviews of literature describing purported negative impacts caused by purple loosestrife in North America. Both papers express concern that widespread claims of ecological harm caused by purple loosestrife are largely unproven. In a widely cited review of purple loosestrife literature in North America, Thompson and others [129] describe encroachment of purple loosestrife around the margins of a waterfowl impoundment in central New York. Their estimates of percent of total plant biomass contributed by purple loosestrife along dike areas of the impoundments describe "dramatic" increases over about a 15-year period. Based on visual estimates of plant biomass, the authors contend that native plant species were displaced, vegetation structure was altered, and habitat quality for nesting waterfowl was seriously degraded. The paper by Thompson and others [129] demonstrates how untested hypotheses can be perpetuated in the literature until they become widely accepted, without the benefit of experimental analysis [47]. As emphasized by Anderson [2], "detailed, quantitative data are needed to understand loosestrife's natural history, population dynamics, and impacts on native ecosystems if we are to effectively manage this plant."

Because purple loosestrife has demonstrated strong competitive abilities where it has invaded North American wetland communities, there is concern that it may diminish native plant diversity. For instance, competition with purple loosestrife has been suggested as a contributing factor in the decline of the rare Long's bulrush (Scirpus longii) in Massachusetts [28]. However, studies published to date have failed to demonstrate a deleterious effect of purple loosestrife on native plant diversity. Treberg and Husband [130] examined the association between purple loosestrife abundance and vascular plant richness along the Bar River in Ontario. Purple loosestrife had been present in this area for at least 12 years and there was a wide range in established plant densities. They found no significant (P<0.05) difference in mean species richness associated with the presence or percent cover of purple loosestrife, and no plant species was significantly (P<0.05) more likely to be found in the absence of purple loosestrife than in its presence. Anderson [1] showed no significant (P<0.05) correlation between total species richness and either percent cover, genet density or median age of purple loosestrife, even in plots containing 18-20 year old purple loosestrife plants. He suggested areas with apparent purple loosestrife monocultures perhaps had low species richness to begin with, and species richness more likely resulted from habitat heterogeneity rather than the presence of innately competitive species. More research is needed in this area.

Purple loosestrife colonization has been purported to have detrimental effects on birds, based on: a) creation of unsuitable nesting habitat and b) low food potential of purple loosestrife relative to vegetation it displaces. However, published studies and observations indicate impacts on birds are not yet clear. Marsh wrens prefer cattails to purple loosestrife for nesting [101,142]. There is speculation that invasion of riparian areas in Nebraska may have adverse effects on important night-roosting habitat for migratory sandhill cranes. Purple loosestrife invasion is predicted to have detrimental effects on nesting habitat of black terns and canvasbacks in the north-central United States, but this has not been tested [129]. Whitt et al. [142] found purple loosestrife-dominated habitats had significantly (P=0.003) higher bird densities but significantly (P=0.03) fewer bird species than other habitats. These higher densities were mainly due to increases in populations of a single species, the swamp sparrow.

Purple loosestrife colonization can substantially reduce or eliminate open water in small marsh areas, potentially reducing its usefulness for waterfowl. In areas with substantial seed banks, mudflats that are commonly used as feeding areas by shorebirds are impacted by rapid, dense colonization by purple loosestrife seedlings. Decline in the extent of open water habitats from increased emergent purple loosestrife can retard access to aquatic prey items such as fish and aquatic invertebrates. Important aquatic food plants for wildlife such as pondweeds (Potamogeton spp.) are inhibited under the shade of emergent purple loosestrife [102]. Invading purple loosestrife in coastal British Columbia's Fraser River estuary may have negative effects on detrital food chains [44].

Thompson and others [129] have illustrated how muskrats might interact with purple loosestrife in a manner detrimental to muskrats. Muskrats apparently find stems of purple loosestrife much less palatable then those of cattail, but they do cut purple loosestrife stems. As they forage they favor cattail stems, potentially shifting the competitive balance toward the less palatable purple loosestrife. The ability of muskrats to shift the competitive balance between cattails and purple loosestrife was corroborated by Rawinski [102] from observations of mixed stands where muskrats were present. At a particular site, muskrats removed entire patches of cattail, leaving purple loosestrife the only remaining emergent. Muskrats may further favor purple loosestrife seedling establishment following den construction. This activity can cause substantial soil disturbance that is rapidly colonized by purple loosestrife seedlings during lower summer water levels. Because of their ability to generate new vegetative growth, partially eaten purple loosestrife stems also represent potential new propagules, adding to its competitive advantage [23]. As community composition shifts from cattails to purple loosestrife dominance, habitat quality and subsequent muskrat carrying capacity apparently decline [129].

Conversion of wetland pasture to predominantly purple loosestrife is believed to reduce forage value for livestock and deer [128]. As purple loosestrife density increases and mature plants produce greater numbers of shoots, the woody nature of purple loosestrife stems diminishes forage value [118].

Purple loosestrife may have adverse effects on habitat of the threatened bog turtle, although details are scant [26,67].

Purple loosestrife invasion may be detrimental to production of natural and domestic wild rice in areas of the upper Midwest, particularly in commercial wild rice paddy operations where water level manipulation presents ideal germination conditions. Dense purple loosestrife infestations can also undermine the functionality of drainage waterways, such as irrigation ditches [118].

Water level manipulations in impoundments have been hindered by threat of purple loosestrife invasion. A 1000-fold increase in acreage containing purple loosestrife was noted over a 23-year period in a central New York wetland and the cause was speculated to be recurrent drawdown of impoundments [102]. In areas managed for waterfowl production, such as many federal and state wildlife refuges, water level drawdowns in impoundments may provide establishment opportunities for purple loosestrife. Drawdowns are often executed to encourage recruitment of plants valuable to waterfowl such as cattails, smartweed (Polygonum spp.) and wild millet (Echinochloa spp.) on exposed soils [90].

Invading purple loosestrife is being monitored in the middle Snake River corridor in Idaho for effects on stream channel dynamics. Purple loosestrife is colonizing gravel bars under low flow conditions. Once established, it appears able to withstand inundation and flowing water conditions better than native annuals. It is feared that persistent purple loosestrife plants may contribute substantially to sediment trapping, leading to gravel bar aggradation, closure of small channels, and despoiling of secure, predator-free island nesting habitat for local waterfowl [32].

Control: Land managers concerned about invasive purple loosestrife should focus on eliminating small, recently-established populations before tackling large, well-established populations. Buildup and persistence of purple loosestrife seed in the soil seed bank appears to be the most problematic, long-term obstacle in eradicating, or at least controlling purple loosestrife. Preventing seed production and seed bank accumulation within recently-established stands is a pragmatic goal, especially in the face of limited resources and knowledge [138,139]. Welling and Becker [138] demonstrated the potential difficulty managers face with attempts to exhaust seed banks in areas where purple loosestrife is well established, although not necessarily monodominant. Because seed dormancy is enforced by burial at relatively shallow (>0.8 inch (2 cm)) depth, and because purple loosestrife seed banks may contain thousands of seeds per square foot at these depths, even successful eradication of extant adult plants and new recruits from near-surface germinants may not suffice for successful long-term control. Even the ability to exhaust near-surface (<0.4 inch (1 cm)) seed banks by promoting germination and removing emergent seedlings is in question.

Any disturbance or management activity that fragments live stem or root tissue is likely to result in the spread, rather than containment of purple loosestrife [23,118]. Live stems that are dislodged and buried can give rise to new shoots via adventitious buds [23,129]. Carp may play an important role where they co-occur with purple loosestrife. Carp eat the roots of purple loosestrife, sometimes until the plants are dislodged and float away. These plants then become potential propagules if they lodge on suitable substrate [102].

Detection and control efforts may be hindered by purple loosestrife's propensity to occasionally remain dormant for an entire growing season. Some plants fail to generate aboveground shoots during a particular year, but exhibit normal growth from the same rootstock in preceding and following years [42,129].

Prevention: It is important to avoid management activities that may enhance the risk of purple loosestrife invasion and expansion. Examples of mitigative efforts are a) encourage establishment, growth, or perpetuation of native woody cover that might provide enough shade to depress or discourage purple loosestrife, b) minimize water level fluctuations in manipulated wetlands or waterways that might encourage establishment of purple loosestrife seedlings, especially early-season drawdowns that expose bare substrate, and c) avoid any form of stress or disturbance to extant native plant communities in susceptible areas, such as disturbing soil with heavy machinery, and where such activities are unavoidable, monitoring impacted areas to detect invaders [129].

Periodic, systematic monitoring of susceptible habitats is strongly encouraged [144]. Development of local populations, as expressed by percent biomass constituted by purple loosestrife, is roughly a logistic function through time. Initial rate of spread of local infestations is slowed when extant competition is strong. As a result, early detection and eradication of colonizing plants is highly preferred. Fortunately, early detection is aided by the tall, showy flower stalks and lengthy period of bloom. Once purple loosestrife becomes strongly established, with many (>10) flowering stems per rootstock, multiple clumps forming monospecific patches or stands, and establishment of a seed bank, eradication becomes more expensive, intrusive, and difficult [129].

Spread of purple loosestrife in natural areas likely has been accelerated by the development, sale and use of various loosestrife cultivars for horticultural purposes. Sale and utilization of ornamental loosestrife cultivars should be curtailed to prevent the risk of further dissemination into previously uncolonized areas. Cultivars are capable of contributing viable seed and pollen to wild populations, and claims of sterile hybrids have been shown to be mainly false [3,74,92].

As with most invasive species, public education plays an important role in preventing establishment and spread of purple loosestrife. Planting of loosestrife cultivars for horticultural purposes should be strongly discouraged. Individuals who frequent areas susceptible to invasion can aid in prevention by washing boots, clothing, equipment, etc. before exiting such areas, and should be encouraged to identify and report potential new infestations to authorities.

Integrated management: A single method may not be effective for long-term control or removal of purple loosestrife. Integrated management involves using several management techniques in a well-planned, coordinated and organized program. Many combinations of control methods can achieve desired objectives. Methods selected for a specific site will be determined by land-use objectives, desired plant community, extent and nature of infestation, environmental factors (nontarget vegetation, habitat types, climate, hydrology, etc.), economics, and effectiveness and limitations of available control techniques [103,114].

Cultural: Seeding of competitive vegetation in areas where bare soil has been exposed may be a useful mitigative measure. This may be especially helpful where presence of seed in the soil seed bank indicates potential for robust purple loosestrife regeneration. Experiments examining the effectiveness of seeding Japanese millet (Echinochloa esculenta) to reduce the impact of purple loosestrife recruitment have shown mixed results [80,140]. In addition to providing competition against purple loosestrife seedlings, Japanese millet may be used by waterfowl and is thought to represent a minimal threat of invasiveness, although it is not native to North America [129]. Seeding native species may provide a desirable postdisturbance community, but explicit tests of the competitive abilities of various native plants when seeded with purple loosestrife are lacking. Seeding of competitors should take place immediately following exposure of soil to maximize their competitive abilities [80].

Flooding infested areas by raising water levels for extended periods may eliminate purple loosestrife from impoundment sites [46]. Flooding duration is more likely to influence mortality than depth of flooding, but specific guidelines are lacking [9]. Persistent high water conditions can slow the growth and reproductive capacity of purple loosestrife and over several years may eliminate extant stands, but results are variable and interactions with other factors poorly understood [80]. In plots subjected to consistently high water levels (16 inch (40 cm) mean depth)), competition with narrow-leaved cattail significantly (P<0.001) reduced stem densities of purple loosestrife compared with flooded stands where purple loosestrife was the predominant species [101]. More research is needed to determine optimal flooding duration and factors that influence variability in the effect of flooding duration [9].

Effectiveness of flooding as a control measure may be enhanced by cutting purple loosestrife stems prior to raising water levels [80]. Cut material should always be removed from the site to prevent spread of vegetative propagules. The efficacy of flooding may be influenced by the presence of carp within contiguous waterways, although the ultimate effects are unclear. Carp may reduce purple loosestrife by grazing its roots or enhance its spread by disseminating vegetative propagules [102]. Carp are not native to North America and should not be introduced as a means to control purple loosestrife.

Consistent spring and early-summer flooding may inhibit purple loosestrife seedling establishment [9,137]. Flooding seedlings 0.8 to 4 inches (2-10 cm) tall for 9 weeks at depths up to 12 inches (30 cm) did not significantly (P<0.05) reduce mean stem densities. Most plants continued to grow, if slowly, while submerged, and plants which emerged above the surface quickly resumed rapid growth [52]. Established purple loosestrife plants can survive in deepwater emergent habitat, in part by development of aerenchymous (containing large intercellular air spaces) stem tissue that facilitates gas exchange in aquatic environments.

Several factors may hinder the effectiveness of controlling purple loosestrife by flooding. Managers may be constrained in their ability to manipulate water levels by the geologic profile of the site or by development along its margins. Substantial warm season evaporation can contribute to this problem. Sustained high water levels may be detrimental to desirable native emergent or shoreline vegetation. Once purple loosestrife has been killed, managers should consider species composition within the remnant seed bank, and the ensuing colonizing community, when water levels have been reduced. It is likely that purple loosestrife seedlings will recolonize the newly exposed soil and further management may be inevitable.

Physical/mechanical: Cutting stems or removing flower heads prior to seed dissemination can prevent local seed bank accumulation. Late-summer cutting appears to reduce vegetative growth more effectively than mid-summer treatments. However, cutting stems is unlikely to prevent perennial stem growth [46,102]. Cutting flower heads may be useful in preventing further seed production when primary control activities, such as herbicide application, require more than 1 season to completely eradicate purple loosestrife [13]. Cutting purple loosestrife stems underwater at various times in summer was ineffective [51].

Digging or hand-pulling plants is recommended for early infestations or a few scattered plants. Digging or pulling young plants in recently colonized areas can be effective in preventing establishment of dense, intractable stands and buildup of substantial seed banks. Early detection is important since established plants may rapidly become too large and deep-rooted for easy removal [102,129]. Because growing points of the plant are located on the root crown, removal of as much rootstock as possible is strongly encouraged [23,46]. Pulling entire plants is easiest when the soil is wet [102,131]. All pulled plant material should be removed from the site to prevent vegetative reproduction from discarded fragments [23]. Spot spraying individual plants with herbicide may be less time and labor intensive when infestations become too large for removal by pulling or digging [129].

Fire: See Fire Management Considerations.

Biological: The objective of biological control is to re-establish ecological relationships that have evolved between purple loosestrife and its native predators in order to suppress invasive populations and reduce harmful impacts. Potential advantages of biological control are cost effectiveness at large scales, sustainability, and benign effects in the nontarget environment [22,131]. The Nature Conservancy's Weed Control Methods Handbook provides a comprehensive discussion of considerations and safety issues in developing and implementing a biological control program.

Plant communities where purple loosestrife is found are similar in North America and Europe. Because native insect herbivory inhibits purple loosestrife performance in Europe, it is hoped introductions of European insect herbivores may work to reduce the competitiveness of purple loosestrife in North America, while releasing native plants from suppression [18,19].

The following table lists non-native insects released in North America to control purple loosestrife:

Control Agent Mode of Action Release Sites
Galerucella calmariensis (beetle) Larvae and adults feed on foliage and flowers  MB, ON
Galerucella pusilla (beetle) Larvae and adults feed on foliage and flowers [18] MB, ON, WA [29,31,97]
Hylobius transversovittatus (weevil) Larvae and adults feed on roots [17] WA [97]
Nanophyes marmoratus (weevil) Larvae feed on flowers and adults feed on foliage and flowers [21] MB [49]

Galerucella beetles have been the most effective biocontrol agents used against purple loosestrife in North America thus far [29,62,97]. G. calmariensis and G. pusilla are similar in appearance and habit and are most effective when released together, and both species appear to be unaffected by exposure to the herbicides glyphosate and triclopyr [75,76]. Because of "dramatic" success at some Galerucella release sites, release of other agents should focus on sites where Galerucella have been ineffective. In Europe, H. transversovittatus herbivory on purple loosestrife is strongest in the northern range of the plant, indicating that higher latitude sites may be a good choice for its release in North America [50].

Myzus lythri, a European aphid that has probably been present in the Eastern United States since the early 1930's, might become an effective biological control agent. It has a host-alternating life cycle, utilizing loosestrife and Epilobium spp. in summer and Prunus spp. as primary hosts the rest of the year. Populations of M. lythri could be manipulated to impact local purple loosestrife populations by mass-rearing bugs for targeted early-spring release and/or by planting Prunus spp. near targeted sites [134].

Research examining the potential use of pathogenic fungi as biocontrol agents is ongoing [91].

Chemical: A variety of herbicides are effective at controlling purple loosestrife in infested areas. Below is a list of herbicides that have been used effectively against purple loosestrife in North America, as well as a brief discussion of important considerations regarding their use. This is not intended as an exhaustive review of chemical control methods. For more detailed information regarding appropriate use of herbicides in natural areas against this and other invasive plant species, see The Nature Conservancy's Weed Control Methods Handbook.

Chemical Considerations
2,4-D [13,90,118,140] Mixed results against purple loosestrife; harmful to dicots, but little impact on neighboring monocots
Triclopyr [12,38,61,89,118] Generally effective at killing purple loosestrife; results are variable with spray volume; selective against dicots
Glyphosate [12,80,102,104,118,122,131] Highly effective against purple loosestrife; specific formulations available for use in aquatic environments; also damages or kills most other plants which it contacts
Imazapyr [11] Effective against purple loosestrife; negatively impacts cattail

A serious challenge to controlling purple loosestrife infestations with herbicides is preventing its re-establishment from the seed bank. In the presence of large purple loosestrife seed banks, removal of a considerable fraction of extant vegetation (weed or otherwise) can result in a dense monoculture of purple loosestrife seedlings. The result may be a worse infestation than was originally present [90]. Broadcast application of broad-spectrum herbicides, such as glyphosate, will likely result in widespread exposure of bare substrate and a dense, monotypic stand of purple loosestrife seedlings [118]. By carefully targeting glyphosate spray application to only purple loosestrife, damage to nontarget plants can be minimized. Continued careful treatments over several years can eventually reduce dense populations of purple loosestrife to minimal levels while promoting native plants [104,122]. Native plants are not just inherently valued, but can also provide competition against inevitable purple loosestrife recruitment from existing seed banks [118].

An apparent tradeoff exists when determining the best time to treat adult stands with herbicides. Managers must attempt to balance preventing seed production in established plants with treatments early in the growing season and preventing establishment of a viable new stand of purple loosestrife seedlings by delaying treatments long enough to inhibit recruitment. By conducting herbicide treatments on adult plants late in the growing season, newly established seedlings may not develop sufficiently to survive winter [89]. Late-summer herbicide application also appears to reduce negative effects on desirable native plants [80]. Rawinski [102] found that glyphosate application during late-bloom (mid-August in central New York) period, compared with late-vegetative (mid-June) period, resulted in fewer loosestrife seedlings the following season and increased presence of naturally established, beneficial plants such as shallow sedge (Carex lurida), rice cutgrass (Leersia oryzoides), smartweed and marsh seedbox (Ludwigia palustris). Late-season application of glyphosate in Minnesota wetlands tended to reduce cattail mortality compared with mid-summer treatments, perhaps because the onset of cattail senescence reduced herbicide uptake [12].

Another tradeoff exists between spray volume and target vs. nontarget effects. Purple loosestrife in Wisconsin was examined for response to variation in spray coverage of glyphosate (Rodeo at 1.5%). Individual genets were spot treated in mid-September and received either low (10-25% leaf area coverage), medium (40-60%), or high (75-90%) dosages. Reduction in adult purple loosestrife density was greatest in the high dosage treatment (90-100% reduction) and lowest in the low dosage treatment (75-90% reduction). Surviving purple loosestrife plants in all treatments were greatly reduced in size and vigor. Because glyphosate is nonselective in its effect, survival of nontarget vegetation was also closely related to dosage. High dosage treatment resulted in dense stands of purple loosestrife seedlings with little to no interspecific competition. In contrast, low dosage treatment resulted in high survival rates of desirable perennials and greatly reduced germination of purple loosestrife seedlings. Effective long-term control of purple loosestrife with glyphosate might best be achieved using low-dosage spot applications and conducting followup treatments in subsequent years as necessary [104].

To minimize non-target effects, managers in Michigan have developed a cut-and-herbicide method for purple loosestrife control. They propose cutting plants high on the stem (just below infloresence), allowing them to continue growing and better absorb the applied herbicide throughout the entire plant. Cutting too low apparently risks forcing the plant to "give up" on the leader and instead producing new ramets from the rootstock. Sponge applicators have been developed that limit contact between chemicals and nontarget plants [131]. These methods may be particularly useful in areas where mitigation of damage to indigenous species is important. Encouraging competition from extant native plants often helps reduce the vigor of invasives. For more detailed information regarding these methods, see Tu [131] and the TNC Weed Control Methods Handbook.

  • 1. Anderson, Mark G. 1991. Population structure of Lythrum salicaria in relation to wetland community structure. Durham, NH: University of New Hampshire. 93 p. Thesis. [39754]
  • 2. Anderson, Mark G. 1995. Interactions between Lythrum salicaria and native organisms: a critical review. Environmental Management. 19(2): 225-231. [37517]
  • 9. Balogh, Gregory Robert. 1986. Ecology, distribution, and control of purple loosestrife (Lythrum salicaria) in northwest Ohio. Columbus, OH: Ohio State University. 122 p. Thesis. [40074]
  • 21. Blossey, Bernd; Schroeder, Dieter. 1995. Host specificity of three potential biological weed control agents attacking flowers and seeds of Lythrum salicaria (purple loosestrife). Biological Control. 5: 47-53. [37523]
  • 23. Brown, Beverly J.; Wickstrom, Conrad E. 1997. Adventitious root production and survival of purple loosestrife (Lythrum salicaria) shoot sections. Ohio Journal of Science. 97(1): 2-4. [37526]
  • 32. Dixon, Mark D.; Johnson, W. Carter. 1999. Riparian vegetation along the middle Snake River, Idaho: zonation, geographical trends, and historical changes. Great Basin Naturalist. 59(1): 18-34. [37548]
  • 80. Malecki, Richard A.; Rawinski, Thomas J. 1985. New methods for controlling purple loosestrife. New York Fish and Game Journal. 32(1): 9-19. [18331]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 128. Thompson, Daniel Q. 1989. Control of purple loosestrife. Fish and Wildlife Leaflet 13.4.11. Washington, DC: U.S. Department of Interior, Fish and Wildlife Service. 6 p. [18333]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 130. Treberg, Michael A.; Husband, Brian C. 1999. Relationship between the abundance of Lythrum salicaria (purple loosestrife) and plant species richness along the Bar River, Canada. Wetlands. 19(1): 118-125. [37542]
  • 138. Welling, Charles H.; Becker, Roger L. 1990. Seed bank dynamics of Lythrum salicaria L.: implications for control of this species in North America. Aquatic Botany. 38(2-3): 303-309. [17423]
  • 139. Welling, Charles H.; Becker, Roger L. 1992. Life history and taxonomic status of purple loosestrife in Minnesota: implications for management and regulation of this exotic plant. Special Publication 146. St. Paul, MN: Department of Natural Resources, Division of Fish and Wildlife. 15 p. [40255]
  • 140. Welling, Charles H.; Becker, Roger L. 1993. Reduction of purple loosestrife establishment in Minnesota wetlands. Wildlife Society Bulletin. 21(1): 56-64. [37502]
  • 3. Anderson, Neil O.; Ascher, Peter D. 1993. Male and female fertility of loosestrife (Lythrum) cultivars. Journal of the American Horticultural Society. 118(6): 851-858. [40318]
  • 11. Becker, Roger L.; Warnes, Dennis D.; Kinkaid, Bradley D.; Miller, Douglas W. 1990. Purple loosestrife control with 1989 applications of triclopyr and imazapyr and commercial standards, Morris, MN. North Central Weed Science Society Research Report. 47: 75-76. [40213]
  • 12. Becker, Roger L.; Warnes, Dennis D.; Ralston, Dennis F. 1989. Purple loosestrife control in 1989 with 1988 applications of triclopyr, White Bear Lake and Morris, MN. North Central Weed Science Society Research Report. 46: 103. [40212]
  • 13. Benedict, Jim. 1990. Purple loosestrife control in Voyageurs National Park. Park Science: A Resource Management Bulletin. 10(3): 21-22. [12720]
  • 17. Blossey, Bernd. 1993. Herbivory below ground and biological weed control: life history of a root-boring weevil on purple loosestrife. Oecologia. 94: 380-387. [40092]
  • 18. Blossey, Bernd. 1995. Impact of Galerucella pusilla and G. calariensis (Coleoptera: Chrysomelidae) on field populations of purple loosestrife (Lythrum salicaria). In: Delfosse, E. S.; Scott, R. R., eds. Proceedings, 8th international symposium on biological control of weeds; 1992 February 2-7; Canterbury, New Zealand. Melbourne, Australia: DSIR/CSIRO: 27-31. [40248]
  • 19. Blossey, Bernd; Notzold, Rolf. 1995. Evolution of increased competitive ability in invasive nonindigenous plants: a hypothesis. Journal of Ecology. 83: 887-889. [39780]
  • 26. Bury, R. Bruce. 1979. Review of the ecology and conservation of the bog turtle, Clemmys muhlenbergii. Special Scientific Report--Wildlife No. 219. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 9 p. [40263]
  • 28. Coddington, Jonathan; Field, Katharine G. 1978. Rare and endangered vascular plant species in Massachusetts. Cambridge, MA: New England Botanical Club. 52 p. [40282]
  • 31. Diehl, Jason K.; Holliday, N. J.; Lindgren, C. J.; Roughley, R. E. 1997. Insects associated with purple loosestrife, Lythrum salicaria L., in southern Manitoba. Canadian Entomologist. 129: 937-948. [39781]
  • 38. Gabor, T. Shane; Haagsma, T.; Murkin, H. R.; Armson, E. 1995. Effects of triclopyr amine on purple loosestrife and non-target wetland plants in south-eastern Ontario, Canada. Journal of Aquatic Plant Management. 33: 48-51. [37505]
  • 41. Gaudet, Connie L.; Keddy, Paul A. 1995. Competitive performance and species distribution in shoreline plant communities: a comparative approach. Ecology. 76(1): 280-291. [37524]
  • 42. Gilbert, N.; Lee, S. B. 1980. Two perils of plant population dynamics. Oecologia. 46: 283-284. [40247]
  • 44. Grout, Jeff A.; Levings, Colin D.; Richardson, John S. 1997. Decomposition rates of purple loosestrife (Lythrum salicaria) and Lyngbyei's sedge (Carex lyngbyei) in the Fraser River estuary. Estuaries. 20(1): 96-102. [37537]
  • 47. Hager, Heather A.; McCoy, Karen D. 1998. The implications of accepting untested hypotheses: a review of the effects of purple loosestrife (Lythrum salicaria) in North America. Biodiversity and Conservation. 7(8): 1069-1079. [37538]
  • 51. Haworth-Brockman, Margaret J.; Murkin, H. R.; Clay, R. T.; Armson, E. 1991. Effects of underwater clipping of purple loosestrife in a southern Ontario wetland. Journal of Aquatic Plant Management. 29: 117-118. [19420]
  • 52. Haworth-Brockman, Margaret J.; Murkin, Henry R.; Clay, Robert T. 1993. Effects of shallow flooding on newly established purple loosestrife seedlings. Wetlands. 13(3): 224-227. [37516]
  • 61. Katovich, Elizabeth J. Stamm; Becker, Roger L.; Kinkaid, Brad D. 1996. Influence of nontarget neighbors and spray volume on retention and efficacy of triclopyr in purple loosestrife (Lythrum salicaria). Weed Science. 44(1): 143-147. [37520]
  • 62. Katovich, Elizabeth J. Stamm; Becker, Roger L.; Ragsdale, David W. 1999. Effect of Galerucella spp. on survival of purple loosestrife (Lythrum salicaria) roots and crowns. Weed Science. 47(3): 360-365. [37512]
  • 65. Keddy, Paul A.; Twolan-Strutt, Lisa; Wisheu, Irene C. 1994. Competitive effect and response rankings in 20 wetland plants: are they consistent across three environments? Journal of Ecology. 82: 635-643. [23700]
  • 66. Keddy, Paul; Fraser, Lauchlan H.; Wisheu, Irene C. 1998. A comparative approach to examine competitive response of 48 wetland plant species. Journal of Vegetative Science. 9(6): 777-786. [37551]
  • 67. Kiviat, Erik. 1978. Bog turtle habitat ecology. Bulletin of the Chicago Herpetological Society. 13: 29-42. [40232]
  • 74. Lindgren, Cory J.; Clay, Robert T. 1993. Fertility of `Morden Pink' Lythrum virgatum L. transplanted into wild stands of L. salicaria L. in Manitoba. HortScience. 28(9): 954. [37504]
  • 75. Lindgren, Cory John; Gabor, T. Shane; Murkin, Henry R. 1998. Impact of triclopyr amine on Galerucella calmariensis L. (Coleoptera: Chrysomelidae) and a step toward integrated management of purple loosestrife Lythrum salicaria L. Biological Control. 12(1): 14-19. [37508]
  • 76. Lindgren, Cory John; Gabor, T. Shane; Murkin, Henry R. 1999. Compatibility of glyphosate with Galerucella calmariensis; a biological control agent for purple loosestrife (Lythrum salicaria). Journal of Aquatic Plant Management. 37: 44-48. [37540]
  • 78. Mal, Tarun K.; Lovett-Doust, Jon; Lovett-Doust, Lesley. 1997. Time-dependent competitive displacement of Typha angustifolia by Lythrum salicaria. Oikos. 79(1): 26-33. [37498]
  • 89. Nelson, Linda S.; Getsinger, K. D.; Freedman, J. E. 1996. Efficacy of triclopyr on purple loosestrife and associated wetland vegetation. Journal of Aquatic Plant Management. 34: 72-74. [37507]
  • 90. Notestein, Anne. 1986. The spread and management of purple loosestrife (Lythrum salicaria L.) in Horicon National Wildlife Refuge, Wisconsin. Madison, WI: University of Wisconsin. 126 p. Thesis. [40233]
  • 91. Nyvall, Robert F.; Hu, An. 1997. Laboratory evaluation of indigenous North American fungi for biological control of purple loosestrife. Biological Control. 8(1): 37-42. [37522]
  • 92. Ottenbreit, Kimberly A.; Staniforth, Richard J. 1994. Crossability of naturalized and cultivated Lythrum taxa. Canadian Journal of Botany. 72: 337-341. [40288]
  • 97. Piper, G. L. 1996. Biological control of the wetlands weed purple loosestrife (Lythrum salicaria) in the Pacific northwestern United States. Hydrobiologia. 340: 291-294. [39782]
  • 101. Rawinski, Thomas J.; Malecki, Richard A. 1984. Ecological relationships among purple loosestrife, cattail and wildlife at the Montezuma National Wildlife Refuge. New York Fish and Game Journal. 31(1): 81-87. [18330]
  • 104. Reinartz, James A.; Popp, James W.; Kuchenreuther, Margaret A. 1986. Purple loosestrife control: minimum glyphosate dose sought (Wisconsin). Restoration & Management Notes. 4(2): 83-84. [40243]
  • 114. Sheley, Roger L.; Kedzie-Webb, Susan; Maxwell, Bruce D. 1999. Integrated weed management on rangeland. In: Sheley, Roger L.; Petroff, Janet K., eds. Biology and management of noxious rangeland weeds. Corvallis, OR: Oregon State University Press: 57-68. [35710]
  • 122. Spinks, Preston; Packard, Stephen. 1988. Control of purple loosestrife (Illinois). Restoration & Management Notes. 6(1): 50. [5555]
  • 134. Voegtlin, David J. 1995. Potential of Myzus lythri (Homoptera: Aphididae) to influence growth and development of Lythrum salicaria (Myrtiflorae: Lythraceae). Biological Control. 24(3): 724-729. [37513]
  • 136. Weiher, Evan; Keddy, Paul A. 1995. The assembly of experimental wetland plant communities. Oikos. 73(3): 323-335. [37497]
  • 137. Weiher, Evan; Wisheu, Irene C.; Keddy, Paul A.; Moore, Dwayne R. J. 1996. Establishment, persistence, and management implications of experimental wetland plant communities. Wetlands. 16(2): 208-218. [37514]
  • 142. Whitt, Michael B.; Prince, Harold H.; Cox, Robert R., Jr. 1999. Avian use of purple loosestrife dominated habitat relative to other vegetation types in a Lake Huron wetland complex. The Wilson Bulletin. 111(11): 105-114. [37525]
  • 144. Zamora, David L.; Thill, Donald C. 1999. Early detection and eradication of new weed infestations. In: Sheley, Roger L.; Petroff, Janet K., eds. Biology and management of noxious rangeland weeds. Corvallis, OR: Oregon State University Press: 73-84. [35712]
  • 22. Bourchier, R. S.; DeClerck-Floate, R. A. 2000. Weed biological control and insect ecology, [Online]. In: Agriculture and Agri-Food Canada, Research Branch, Lethbridge Research Centre, Biocontrol Projects. Available: http://res2.agr.ca/lethbridge/crops/bioproj.htm [2002, March 23]. [40342]
  • 29. Corrigan, J. E.; Mackenzie, D. L.; Simser, L. 1998. Field observations of non-target feeding by Galerucella calmariensis [Coleoptera: Chrysomelidae], an introduced biological control agent of purple loosestrife, Lathrum salicaria [Lythraceae]. Proceedings, Entomological Society of Ontario. 129: 99-106. [37533]
  • 46. Haber, Erich. 2001. Invasive plant data summary and control options: Purple loosestrife. In: Invasive plants of Canada: Guide to species and methods of control, [Online]. Available: http://www.magi.com/%%7Eehaber/lyth_sal.html [2002, January 25]. [40051]
  • 49. Harris, P. 2002. Established biocontrol agent: Nanophyes marmoratus (Goeze). flower-feeding weevil, [Online] In: Biological control of weeds--Biology of target weeds. Lethbridge, AB: Agriculture and Agri-Food Canada, Research Branch, Lethbridge Research Centre (producer). Available: http://res2.agr.ca/lethbridge/weedbiol/agents/ananmar.htm [2002, March 23]. [40344]
  • 50. Harris, P.; Corrigan, J. 2000. Purple loosestrife (Lythrum salicaria L.), [Online]. In: Biological control of weeds--Biology of target weeds. Lethbridge, AB: Agriculture and Agri-Food Canada, Research Branch, Lethbridge Research Centre (producer). Available: http://res2.agr.ca/lethbridge/weedbio/hosts/blosstrf.htm [2002, January 25]. [39822]
  • 103. Rees, N. E.; Quimby, P. C., Jr.; Mullin, B. H. 1996. Section I. Biological control of weeds. In: Rees, Norman E.; Quimby, Paul C., Jr.; Piper, Gary L.; [and others], eds. Biological control of weeds in the West. Bozeman, MT: Western Society of Weed Science. In cooperation with: U.S. Department of Agriculture, Agricultural Research Service; Montana Department of Agriculture; Montana State University: 3-24. [38273]
  • 131. Tu, Mandy, ed. 2000. Techniques from TNC stewards for the eradication of Lythrum salicaria (purple loosestrife) and Phragmites australis (common reed/Phrag) in wetlands. In: Control comments from stewards. Weeds on the web: Wildland invasive species program, [Online]. Available: http://tncweeds.ucdavis.edu/esadocs/lythsali.html. [40056]

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Prevention and Control

Small infestations of young purple loosestrife plants may be pulled by hand, preferably before seed set. For older plants, spot treatment with a glyphosate-based herbicide such as Rodeo® for wetlands or near water and Roundup® for uplands may be effective. Biological control, using several imported beetle species approved by the USDA for release, is the most effective method for long-term control of large infestations.

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Control

Please contact your local agricultural extension specialist or county weed specialist to learn what works best in your area and how to use it safely. Always read label and safety instructions for each control method. Trade names and control measures appear in this document only to provide specific information. USDA, NRCS does not guarantee or warranty the products and control methods named, and other products may be equally effective.

An important consideration in controlling purple loosestrife is its prolific seed production, the ease with which seeds are dispersed, and their ability to remain viable for several years. Also, this plant can spread vegetatively by resprouting from stem and rootstock cuttings. Other considerations in selecting control methods are their detrimental effects on native species and the possibility for reinvasion by purple loosestrife or other exotic species. In addition, native plants of similar appearance should not be subjected to control. Purple loosestrife may superficially resemble plants of the mint family or species of the genera Epilobium and Liatris. Proper identification is an important consideration in controlling exotic loosestrife.

In natural areas, it may be more feasible to contain populations of purple loosestrife than control them. Large populations extending over one hectare or more will be difficult to eradicate. Containing them may be more feasible. Removing plants or applying herbicides to ones extending beyond the main population can accomplish this. If loosestrife cannot be eradicated, efforts should then concentrate on keeping it from invading the highest quality areas (Butterfield et al., 1996.

Manual, Mechanical, and Replacement: Mowing, burning, and flooding are largely ineffective. Cutting followed by flooding so that cut plant stalks are completely immersed has shown some success. However, flooding may encourage the spread of purple loosestrife seed present in the soil and may result in the regeneration of new plants from stem fragments. Mature plants can withstand short-term immersion. Burning is largely ineffective and it may also stress native plants and subsequently enhance loosestrifes’ competitive advantage (Butterfield et al., 1996).

Hand removal is effective for small populations and isolated plants. Younger plants (one to two years old) can be pulled by hand. Plants should be removed, prior to seed set, with minimal disturbance to the soil. Removal after seed-set will scatter the seeds. The entire rootstock must be pulled out because of the potential for regeneration from root fragments. A hand cultivator or similar implement will be helpful for older plants, especially those in deep organic soils. Uprooted plants and broken stems need to be removed from the site since such fragments can re-sprout. Bagging plants for removal will prevent their spread along the exit route. Follow-up treatments are recommended for three years after plants are removed. Clothing and equipment used during plant removal should be cleaned to remove contaminating seeds.

Replacement control has been attempted in several wildlife refuges. Research has shown that Japanese millet (Echinochloa frumentacea Link) seedlings outcompete purple loosestrife seedlings. The millet must be planted immediately after marsh drawdown and replanted each year because it does not regenerate well. Replacement seeding trials using native pale smartweed (Polygonum lapathifolium L.) showed that it also out-competed purple loosestrife. Replacement methods have obvious limited application in natural areas, but they may provide control of loosestrife populations on bordering property (Butterfield et al. 1996).

Herbicide Control: Various chemical treatments have been used on purple loosestrife with varying success. Many herbicides are not specific to purple loosestrife and may not be specifically licensed for such use. Label directions for application and use according to local, state, and federal regulations must always be observed.

In areas with populations exceeding 100 plants (up to 1.6 ha in size) where hand-pulling is not feasible, application of a glyphosate herbicide to individual purple loosestrife plants provides effective control Glyphosate is available under the trade names Roundup® and Rodeo®. Rodeo is registered for use over open water and is the most commonly used herbicide to control purple loosestrife. Glyphosate is nonselective and can kill desirable plants associated with loosestrife if applied carelessly. Application to the tops of plants alone can be effective and limits exposure of non-target species (Butterfield et al. 1996).

Herbicide treatment should be conducted as early as possible during the manufacturer's recommended time of application in order to kill the plants and prevent seed production. Application is most effective when plants have just begun flowering. Timing is important because seed set can occur if plants are in mid- to late flower. Where possible, the flower heads should be cut, bagged, and removed from the site prior to application to prevent seed set. Rodeo applied as a 1.5% solution (2 oz. Rodeo/gallon clean water) with the addition of a wetting agent, as specified on the label has been shown to provide control. Another option, which may be more effective, is to apply glyphosate twice during the growing season. The plants should be sprayed as described above when flowering has just started and a second time two to three weeks later (Butterfield et al. 1996).

Application of ghyphosate from a vehicle-mounted sprayer is generally necessary in areas with extensive stands of purple loosestrife. The most effective control can be achieved by beginning treatment at the periphery of large patches and working toward the center in successive years. This technique allows native vegetation to re-invade the treated area as the loosestrife in eliminated (Butterfield et al. 1996).

A combination of 2,4-D and Banvel® (dicamba) has been used on a limited basis. This formulation is broadleaf specific and apparently would not hurt the dominants if sprayed in a cattail marsh or communities dominated by rushes, sedges, and grasses. Spraying produces good control once loosestrife has reached 10-15% of its mature growth. Treatment is more effective if repeated once during the growing season (Butterfield et al. 1996).

Biological Control: Several biological control agents have the potential to aid in the control of purple loosestrife. Of 120 species of phytophagous insects associated with purple loosestrife in its natural range in Europe, 14 species were considered host-specific to the target plant. From this group, six species have been selected as the most promising for biological control. These species were a root-mining weevil, Hylobius transversovittatus Goeze, which attacks the main storage tissue of purple loosestrife; two leaf-eating beetles, Galerucella calmariensis L., and G. pusilla Duftschmid, which are capable of completely defoliating the plant; two flower-feeding beetles, Nanophyes marmoratus Goeze and N. brevis Boheman, which severely reduce seed production; and a gall midge, Bayeriola salicariae Kieffer, which similarly reduces seed production by attacking the flower buds. Five of the six species are found throughout its range in Europe and the sixth, N. brevis, is restricted to southern Europe (Malecki et al. 1993; Weedin et al. 1996).

The most promising insects appear to be the root-mining weevil, H. transversovittatus, and the two leaf-eating beetles, G. calmariensis and G. pusilla, because of their broad geographic ranges and the amount of damage done to the host plant. In June of 1992, all three species were approved by USDA, APHIS for introduction into the United States. The insects were released in New York, Pennsylvania, Maryland, Virginia, Minnesota, Oregon, and Washington. Releases were also approved in Canada (Malecki et al. 1993).

The two Galerucella species successfully over-wintered and began oviposition at all release sites. The other species, H. transversovittatus, was proving more difficult to establish, because of its long life cycle and low fecundity. The investigators predict that all three species will become established throughout the North American range of purple loosestrife. Furthermore, H. transversovittatus is expected to have the greatest negative impact to L. salicaria. However, a combination of various phytophagous insects will provide greater control than any one species. Control of purple loosestrife will be achieved more rapidly in mixed plant communities where competition for space and nutrients is greater. A reduction in the abundance of purple loosestrife to approximately 10% of its current level over about 90% of its range is expected (Malecki et al. 1993).

In order to evaluate the potential of fungus pathogens to control purple loosestrife, a survey was conducted on fungi associated with that plant. During the three year study, 5265 fungal isolates were obtained. Thirty-one taxa were found that had not previously been reported from purple loosestrife. Tests for the pathogenicity to purple loosestrife are being tested (Nyvall 1995).

Public Domain

USDA NRCS National Plant Data Center & Louisiana State University-Plant Biology; partial funding from the US Geological Survey and the US National Biological Information Infrastructure

Source: USDA NRCS PLANTS Database

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Relevance to Humans and Ecosystems

Benefits

Cultivation

The preference is full or partial sun, wet to moist conditions, and a mucky soil containing organic matter. Ordinary garden soil containing loam is satisfactory as long as there is adequate moisture. This plant can spread aggressively in some situations and can be difficult to destroy. Range & Habitat
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© John Hilty

Source: Illinois Wildflowers

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Cover Value

More info for the term: cover

Purple loosestrife stands may provide cover habitat for wood ducks [121], ring-necked pheasants and cottontail rabbits [120].
  • 120. Smith, Ralph H. 1964. Experimental control of purple loosestrife (Lythrum salicaria). New York Fish and Game Journal. 11(1): 35-46. [18332]
  • 121. Sousa, P. J.; Farmer, A. H. 1983. Habitat suitability index models: wood duck. FWS/OBS-82/10.43. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 27p. [29456]

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Importance to Livestock and Wildlife

More info for the term: swamp

Purple loosestrife shoots may be grazed by white-tailed deer [2,102], muskrat [2,129], and rabbits [2,113], but extent of mammal herbivory is sometimes difficult to determine due to rapid regrowth of multiple new stems from browse points. In a mixed stand of purple loosestrife and cattail, foraging muskrats were observed to occasionally cut stems of purple loosestrife but preferentially fed on roots and overwintering shoots of cattail [102].

While purple loosestrife invasion is often reported as detrimental to wetland-bird habitat, some evidence indicates little to no harmful effect. American coot, pied-billed grebe, black-crowned night heron, American goldfinch and gray catbird have all been observed nesting in purple loosestrife stands [2,102]. Red-winged blackbirds preferentially nest in purple loosestrife over cattails [101,142]. American goldfinch construct nests in purple loosestrife, utilizing the relatively stable stalks to attach nests above the ground or water surface [68]. Pied-billed grebes use dead purple loosestrife stems as nest substrate in habitat with standing and emergent vegetation [77]. In a 2-year survey of birds in wetlands surrounding Lake Huron's Saginaw Bay in eastern Lower Michigan, swamp sparrow nests were most abundant in areas of purple loosestrife dominance [142].

Although purple loosestrife, with its tiny seeds, has been assumed to provide little to no food for birds [129], there are several reports of ducks and red-winged blackbirds consuming purple loosestrife seeds [2], and a report of damage to experimental seedling plots in England caused by ring-necked pheasants and pigeons [113].

  • 2. Anderson, Mark G. 1995. Interactions between Lythrum salicaria and native organisms: a critical review. Environmental Management. 19(2): 225-231. [37517]
  • 102. Rawinski, Thomas James. 1982. The ecology and management of purple loosestrife (Lythrum salicaria L.) in central New York. Ithaca, NY: Cornell University. 88 p. Thesis. [40281]
  • 113. Shamsi, S. R. A.; Whitehead, F. 1977. Comparative eco-physiology of Epilobium hirsutum L. and Lythrum salicaria L. IV. Effects of temperature and inter-specific competition and concluding discussion. Journal of Ecology. 65: 71-84. [39785]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 68. Kiviat, Erik. 1996. American goldfinch nests in purple loosestrife. The Wilson Bulletin. 108(1): 182-186. [39420]
  • 77. Lor, Socheata Krystyne. 2000. Population status and breeding ecology of marsh birds in western New York. Ithaca, NY: Cornell University, Department of Natural Resources. 126 p. Thesis. [40280]
  • 101. Rawinski, Thomas J.; Malecki, Richard A. 1984. Ecological relationships among purple loosestrife, cattail and wildlife at the Montezuma National Wildlife Refuge. New York Fish and Game Journal. 31(1): 81-87. [18330]
  • 142. Whitt, Michael B.; Prince, Harold H.; Cox, Robert R., Jr. 1999. Avian use of purple loosestrife dominated habitat relative to other vegetation types in a Lake Huron wetland complex. The Wilson Bulletin. 111(11): 105-114. [37525]

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Nutritional Value

No information

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Palatability

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Other uses and values

Purple loosestrife was previously used by European immigrants in herbal remedies for a variety of maladies [129]. Purple loosestrife, as well as other loosestrifes, have long been popular with gardeners for their abundant and attractive floral displays and are still sold legally in some places. However, many North American horticulturalists have now abandoned its promotion because of its potential for escape [15,34,48,59,82,129]. It has also been utilized as a honey plant by beekeepers [96,129]. Purple loosestrife seed has occasionally been included in commercial "wildflower" seed mixes [129].
  • 48. Harper, Bonnie L. 1986. A Minnesota counterattack on purple loosestrife (Lythrum salicaria). In: Clambey, Gary K.; Pemble, Richard H., eds. The prairie: past, present and future: Proceedings of the 9th North American Prairie Conference; 1984 July 29 - August 1; Moorhead, MN. Fargo, ND: Tri-College University Center for Environmental Studies: 262-264. [3589]
  • 129. Thompson, Daniel Q.; Stuckey, Ronald L.; Thompson, Edith B. 1987. Spread, impact, and control of purple loosestrife (Lythrum salicaria) in North American wetlands. Fish and Wildlife Research 2. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 55 p. [39777]
  • 96. Pellett, Melvin. 1977. Purple loosestrife spreads down river. American Bee Journal. 117: 214-215. [40055]
  • 15. Berghage, Robert; Sellmer, Jim. 1998. A note on purple loosestrife. Ornamental Horticulture Monthly Newsletter, [Online]. University Park, PA: Penn State University. 1(3), 5ff. Available: http://hortweb.cas.psu.edu/ohortex/news/1998/May_98.html [2002, March 19]. [40340]
  • 34. Ducks Unlimited Canada. 2000. Don't give purple loosestrife a home this summer, [Online]. 2000 News Release. Available: http://www.ducks.ca/NEWS/2000/000526.html [2002, March 3]. [40341]
  • 59. Johnson, Wayne S. 2000. I repent, repent, repent! Kill purple loosestrife--that beautiful weed. Nevada's Horticulture Connection, [Online]. Reno, NV: University of Nevada, Cooperative Extention. 1(1), 3ff. Available: http://www.extension.unr.edu/horticulture/april2000/purpleloosestrife.htmt [2002, March 19]. [40339]
  • 82. Mason, Sandra. 1999. Homeowner's column: Some plants are illegal to grow in Illinois, [Online]. Champaign, IL: University of Illinois at Urbana-Champaign, University Extension, Urban Programs Resource Network (Producer). Available: http://www.urbanext.uiuc.edu/champaign/homwowners/hc990515.html [2002, March 19]. [40336]

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Uses

Noxious and highly invasive.

Ethnobotanic: Immigrants might have deliberately introduced L. salicaria for its value as a medicinal herb in treating diarrhea, dysentery, bleeding wounds, ulcers, and sores, for ornamental purposes, or as a source of nectar and pollen for beekeepers (Hayes 1979; Jones 1976; Malecki et al. 1993; Stuckey 1980). In states where it is permitted, purple loosestrife continues to be promoted by horticulturists for its beauty as a landscape plant and for bee-forage. Purple loosestrife has been of interest to beekeepers because of its nectar and pollen production. However, honey produced from it is apparently of marginal quality (Feller-Demalsy & Parent 1989).

Horticultural: Horticultural cultivars of purple loosestrife (Lythrum spp.) were developed in the mid-1900s for use as ornamentals. Initially, these were thought to be sterile, and therefore safe for horticultural use. Recently, under greenhouse conditions, experimental crosses between several cultivars and wild purple loosestrife and the native L. alatum produced hybrids that were highly fertile (Ottenbreit 1991; Ottenbreit & Staniforth 1994). Comparable, subsequent experiments performed under field conditions produced similar results, suggesting that cultivars of purple loosestrife can contribute viable seeds and pollen that can contribute to the spread of purple loosestrife (Lindgren & Clay 1993). Ottenbreit & Staniforth (1994) indicate that such results suggest the need to prohibit cultivars of this species.

Noxiousness: Purple loosestrife grows most abundantly in parts of Canada, the northeastern United States, the Midwest, and in scattered locations in the West. Although this species tolerates a wide variety of soil conditions, its typical habitat includes cattail marshes, sedge meadows, and bogs. It also occurs along ditch, stream, and riverbanks, lake shores, and other wet areas. In such habitats, purple loosestrife forms dense, monospecific stands that can grow to thousands of acres in size, displacing native, sometimes rare, plant species and eliminating open water habitat. The loss of native species and habitat diversity is a significant threat to wildlife, including birds, amphibians, and butterflies, that depend on wetlands for food and shelter. Purple loosestrife monocultures also cause agricultural loss of wetland pastures and hay meadows by replacing more palatable native grasses and sedges (Mal et al. 1992; Thompson et al. 1987).

Having a noxious weed designation in some states prohibit its importation and distribution, but it is readily available commercially in many parts of the country. Lythrum salicaria has been labeled the “purple plague." because of its epidemic devastation to natural communities. The species is included on the Nature Conservancy’s list of “America’s Least Wanted -The Dirty Dozen” (Flack & Furlow 1996).

Impact/Vectors: Naturalized purple loosestrife was relatively obscure from the time of its introduction into North America in the early 1800s (Pursh 1814) until 1930, when a significant increase in populations invading wetlands and pastures was documented (Strefeler et al. 1996b). Reasons for the apparent sudden colonization and spread of this species include the disturbance of natural systems by human activities including agricultural settlement, construction of transport routes such as canals, highways, and perhaps, nutrient increases to inland waters (Mal et al. 1992; Malecki et al. 1993). Absence of natural enemies and ornamental use are other possible causes for purple loosestrife’s rapid expansion in North America (Thompson et al, 1987). Recently created irrigation systems in many western states have supported further establishment and spread of L. salicaria (Malecki et al. 1993).

The acquisition of adaptive characteristics from native species of Lythrum may have enhanced purple loosestrife’s invasive success. It will hybridize with Lythrum alatum, a widespread, native North American species, in natural settings. Under certain circumstances fertile hybrids are produced that can cross with weedy purple loosestrife. Such interspecific hybrids could serve as a “hybrid bridge” for the transfer of adaptive traits from native L. alatum into weedy populations of purple loosestrife (Anderson & Ascher 1993; Strefeler et al. 1996b).

North American naturalized populations of purple loosestrife often form monospecific stands, whereas, in its native Eurasian habitat the species comprises 1-4% of the vegetative cover (Batra et al. 1986; Strefeler et al. 1996b). Purple loosestrife causes annual wetland losses of about 190,000 hectares in the United States (Thompson et al. 1987; Mal et al. 1997). The species is most abundant in the Midwest and Northeast where it infests about 8,100 hectares in Minnesota, 12,000 ha in Wisconsin, over 12,000 ha in Ohio, and a larger area in New York State. Recent distributional surveys document the occurrence of monocultures in every county in Connecticut, where it has been found in 163 wetland locations (Ellis and Weaver 1996; Ellis 1996). At the Effigy Mounds National Monument (EFMO), combined populations of purple loosestrife cover an area of 5 to 10 hectares growing in regularly disturbed sites. This species has a major visual impact on the vegetation of EFMO, and it has the potential to invade and replace native communities endangering the areas' primary resources. (Butterfield et al. 1996). In response to the alarming spread of this exotic species, at least 13 states (e.g., Minnesota, Illinois, Indiana, Ohio, Washington, and Wisconsin) have passed legislation restricting or prohibiting its importation and distribution (Malecki et al. 1993; Strefeler et al. 1996b).

Numerous studies demonstrate the aggressive and competitive nature of purple loosestrife. Fernald (1940) reported a loss of native plant diversity in the St. Lawrence River floodplain following the invasion of purple loosestrife and another exotic, Butomus umbellatus L. Gaudet and Keddy (1988) report declining growth for 44 native wetland species after the establishment of Lythrum. Among the species tested, Keddy (1990) found that purple loosestrife was the most competitive. His hierarchical rank, arranged from most to least competitive, illustrates the dominance of this invasive weed over many common natives: Lythrum>Cyperus>Juncus> Eleocharis> Mimulus>Verbena. In the Hamilton Marshes adjacent to the Delaware River, annual above-ground production of L. salicaria far exceeded all other plant species’ production combined.

Purple loosestrife provides little food, poor cover, and few nesting materials for wildlife (Mann 1991). Waterfowl nesting becomes more difficult as clumps of L. salicaria restrict access to open water and offer concealing passageways for predators such as foxes and raccoons (Mal et al. 1992). Non-game species, including black terns and marsh wrens, also lose nesting sites when purple loosestrife infests their normal habitats. Balogh and Bookhout (1989a) report that dense stands of purple loosestrife provide poor waterfowl and muskrat habitat. Red-wing blackbirds appear to be the only species to cope with changes in wetlands caused by purple loosestrife (Balogh and Bookhout 1989a). In many areas where L. salicaria populations have increased, wildlife species have declined. While some studies may fail to demonstrate cause and affect relationship, they firmly establish circumstantial evidence implicating that Lythrum’s invasion is responsible for major changes in wetland communities (Mal et al. 1992).

Purple loosestrife prefers moist, highly organic soils but can tolerate a wide range of conditions. It grows on calcareous to acidic soils, can withstand shallow flooding, and tolerates up to 50% shade. Purple loosestrife has low nutrient requirements and can withstand nutrient poor sites. Under experimental, nutrient-deficient conditions, the root/shoot ratio increased and provided purple loosestrife with a competitive advantage over the native species Epilobium hirsutum. Survival and growth of L. salicaria was greatly improved by fertilizer treatment and greater spacing between plants. Such results suggest that excessive use of fertilizers and the release of phosphates, nitrates, and ammonia into the environment has enhanced the success of Lythrum (Mal et al., 1992; Shamsi and Whitehead, 1977a and b).

Purple loosestrife flowers from July until September or October. Flowering occurs 8-10 weeks after initial spring growth. The lowermost flowers of the inflorescence open first and flowering progresses upward. The capsules mature in the same sequence and the lowermost will ripen and disperse its seeds while flowering is still occurring further up the inflorescence (Butterfield et al. 1996). Thompson et al. (1987) estimated that on average, a mature plant produces about 2,700,000 seeds annually. Purple loosestrife seeds are mostly dispersed by water, but wind and mud adhering to wildlife, livestock, vehicle tires, boats, and people serve also as agent. Seeds are relatively long-lived, retaining 80% viability after 2-3 years of submergence (Malecki 1990). Welling & Becker (1990) investigated seed bank dynamics in three wetland sites in Minnesota and noted a mean density of 410,000 seeds per square meter in the top 5 cm of soil, which was more than all other species combined.

Spring-germinated seedlings have a higher survival rate than summer-germinated seedlings. Seedlings that germinate in the spring will flower the first year, whereas, summer-germinated seedlings develop only five or six pairs of leaves before the end of the growing season. Since its seeds are small, weighing about 0.06 mg each and carry little food reserves, germination must occur under conditions where photosynthesis can occur immediately. A strong taproot develops quickly in seedlings and persists throughout the life of the plant. The aerial shoots die in the fall and new shoots arise the following spring from buds on the rootstocks. Shoots destroyed by fire, herbicides, or mechanical removal can also regenerate from the rootstock. As plants mature, they produce more and more aerial shoots forming very dense clumps of growth. Purple loosestrife can spread vegetatively by resprouting from stem cuttings and from regeneration of pieces of root stock (Mal et al. 1992). Rhizomatous growth is insignificant in purple loosestrife (Shamsi & Whitehead 1974a; Thompson et al. 1987).

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USDA NRCS National Plant Data Center & Louisiana State University-Plant Biology; partial funding from the US Geological Survey and the US National Biological Information Infrastructure

Source: USDA NRCS PLANTS Database

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Risks

Stewardship Overview: Monitor natural areas for the presence of L. salicaria. Maintain preserves so that purple loosestrife cannot invade and flourish. For small infestations, eradication is possible with spot applications of glyphosate herbicides. Monitor the containment and control procedures.

Current methods for eradicating large, dense populations of loosestrife are not totally effective. Mechanical contol methods are ineffective, and the herbicide most effective is non-selective. Realistically, the long-term control of large populations may require biological controls and/or better herbicides, but their development is at least several years away. Therefore, containment and minimizing seed production are the present contol objectives for large dense populations. (MN DNR 1987)

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Ecological Threat in the United States

Purple loosestrife adapts readily to natural and disturbed wetlands. As it establishes and expands, it outcompetes and replaces native grasses, sedges, and other flowering plants that provide a higher quality source of nutrition for wildlife. The highly invasive nature of purple loosestrife allows it to form dense, homogeneous stands that restrict native wetland plant species, including some federally endangered orchids, and reduce habitat for waterfowl.

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U.S. National Park Service Weeds Gone Wild website

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Ecological Threat in the United States

Under favorable conditions, purple loosestrife is able to rapidly establish and replace native vegetation with a dense, homogeneous stand that reduces local biodiversity, endangers rare species and provides little value to wildlife.

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Wikipedia

Lythrum salicaria

Lythrum salicaria (Purple loosestrife[1]) is a flowering plant belonging to the family Lythraceae. It should not be confused with other plants sharing the name loosestrife that are members of the family Primulaceae. Other names include spiked loosestrife, or purple lythrum.

Description[edit]

Lythrum salicaria is a herbaceous perennial plant, that can grow 1–1.5 m tall, forming clonal colonies 1.5 m or more in width with numerous erect stems growing from a single woody root mass. The stems are reddish-purple or red to purple and square in cross-section. The leaves are lanceolate, 3–10 cm long and 5–15 mm broad, downy and sessile, and arranged opposite or in whorls of three.

The flowers are reddish purple, 10–20 mm diameter, with six petals (occasionally five) and 12 stamens ( one stamen has up to 3,000 seeds), and are clustered tightly in the axils of bracts or leaves; there are three different flower types, with the stamens and style of different lengths, short, medium or long; each flower type can only be pollinated by one of the other types, not the same type, thus ensuring cross-pollination between different plants.[1][2][3]

The fruit is a small 3–4 mm capsule[4] containing numerous minute seeds. Flowering lasts throughout the summer. When the seeds are mature, the leaves often turn bright red through dehydration in early autumn; the red colour may last for almost two weeks. The dead stalks from previous growing seasons are brown.[1][2][3]

Bright crimson leaves at the onset of autumn

L. salicaria is very variable in leaf shape and degree of hairiness, and a number of subspecies and varieties have been described, but it is now generally regarded as monotypic with none of these variants being considered of botanical significance. The species Lythrum intermedium Ledeb. ex Colla is also now considered synonymous.[1][5][3]

Distribution[edit]

Native to Europe, Asia, northwest Africa, and southeastern Australia.[5][6][2][7]

Ecology[edit]

Found in ditches, wet meadows and marshes and along sides of lakes.[8]

Associated insects[edit]

The flowers are pollinated by long-tongued insects, including bees and butterflies.[3]

A number of insects use Lythrum salicaria as a food resource.

The black-margined loosestrife beetle Galerucella calmariensis is a brown beetle with a black line on its thorax. The adult feeds on the leaves of the plant, producing characteristic round holes. Its larvae destroy tender leaf buds and strip the tissue from the leaves. The golden loosestrife beetle Galerucella pusilla is nearly identical to G. calmariensis, but usually lacks the black thoracic line. Its feeding habits are also quite similar to the other leaf beetle.

The loosestrife root weevil Hylobius transversovittatus is a large red nocturnal weevil, which spends its nights feeding on leaves and leaf buds. The larvae emerge from their eggs and immediately burrow into the root of the plant, which they feed on continuously for over a year. This root damage stunts the plant's growth and ability to create seeds. If several larvae inhabit the same root, the plant can be killed.

The loosestrife flower weevil Nanophyes marmoratus is a tiny weevil which lays a single egg in each flower. When the larvae emerge they eat the flowers' ovaries, and the plant is unable to create seeds. The larvae usually proceed to hollow out the flower buds and use them as safe places to pupate.

Caterpillars of the engrailed moth (Ectropis crepuscularia), a polyphagous geometer moth, also feed on Purple Loosestrife.

Cultivation, uses, and impact[edit]

It has been used as an astringent medicinal herb to treat diarrhea and dysentery; it is considered safe to use for all ages, including babies.[9] It is also cultivated as an ornamental plant in gardens, and is particularly associated with damp, poorly drained locations such as marshes, bogs and watersides. However, it will tolerate drier conditions. The flowers are showy and bright, and a number of cultivars have been selected for variation in flower colour, including:-

  • 'Atropurpureum' with dark purple flowers
  • 'Brightness' with deep pink flowers
  • 'Feuerkerze' with rose-red flowers has gained the Royal Horticultural Society's Award of Garden Merit[10]
  • 'Happy' with red flowers on a short (60 cm) stem
  • 'Purple Spires' with purple flowers on a tall stem
  • 'Roseum Superbum' with large pink flowers.[11]

It has also been introduced in many areas of North America by bee keepers, due to its abundunce of flowers which provide a large source of nectar.

As an invasive species[edit]

Naturalised plants growing in the Cooper Marsh Conservation Area, near Cornwall Ontario.

The purple loosestrife has been introduced into temperate New Zealand and North America where it is now widely naturalised and officially listed in some controlling agents. Infestations result in dramatic disruption in water flow in rivers and canals, and a sharp decline in biological diversity as native food and cover plant species, notably cattails, are completely crowded out, and the life cycles of organisms from waterfowl to amphibians to algae are affected. A single plant may produce up to 2.7 million tiny seeds annually. [12] Easily carried by wind and water, the seeds germinate in moist soils after overwintering. The plant can also sprout anew from pieces of root left in the soil or water. Once established, loosestrife stands are difficult and costly to remove by mechanical and chemical means.

Plants marketed under the name "European wand loosestrife" (L. virgatum) are the same species despite the different name. In some cases the plants sold are sterile, which is preferable.

In North America, purple loosestrife may be distinguished from similar native plants (e.g. fireweed Epilobium angustifolium, blue vervain Verbena hastata, Liatris Liatris spp., and spiraea (Spiraea douglasii) by its angular stalks which are square in outline, as well by its leaves, which are in pairs that alternate at right angle and are not serrated.

Biological control[edit]

Purple loosestrife provides a model of successful biological pest control. Research began in 1985 and today the plant is managed well with a number of insects that feed on it. Five species of beetle use purple loosestrife as their natural food source and they can do significant damage to the plant. The beetles used as biological control agents include two species of leaf beetle: Galerucella calmariensis and Galerucella pusilla, and three species of weevil: Hylobius transversovittatus, Nanophyes breves, and Nanophyes marmoratus. Infestations of either of the Galerucella species is extremely effective in wiping out a stand of purple loosestrife, defoliating up to 100% of the plants in an area. The moth Ectropis crepuscularia is a pest species itself and unsuitable for biological control.[13]

References[edit]

  1. ^ a b c d Flora of NW Europe: Lythrum salicaria
  2. ^ a b c Flora of China: Lythrum salicaria
  3. ^ a b c d Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2
  4. ^ Clapham, A.R., Tutin, T.G. and Warburg, R.F. 1968. Excursion Flora of the British Isles. Cambridge University Press. ISBN 0 521 04656 4
  5. ^ a b Flora Europaea: Lythrum salicaria
  6. ^ Med-Checklist: [ Lythrum salicaria]
  7. ^ Australian Plant Names Index: Lythrum salicaria
  8. ^ Webb, D.A., Parnell, J. and Doogue, D. 1996. An Irish Flora. Dundalgan Press (W.Tempest) Ltd, Dundalk.ISBN 0-85221-131-7
  9. ^ Plants for a Future: Lythrum salicaria
  10. ^ "RHS Plant Selector - Lythrum salicaria 'Feuerkerze'". Retrieved 26 June 2013. 
  11. ^ Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
  12. ^ "Non-native Invasive Freshwater Plants - Purple Loosestrife (Lythrum salicaria)". Retrieved 6 June 2014. 
  13. ^ Wilson, L. M., Schwarzlaender, M., Blossey, B., & Randall, C. B. (2004). Biology and Biological Control of Purple Loosestrife. Morgantown, WV: USDA Forest Health Technology Enterprise Team.
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Notes

Comments

Great variability, especially in degree of indumentum and leaf shape, has led to recognition of many microspecies and infraspecific taxa that are not satisfactorily separated when the species is investigated over its geographic range. Apparent hybridization between Lythrum salicaria and L. virgatum and among the many races of L. salicaria in E Europe and Asia have further confused the taxonomy. Lythrum salicaria is recognized here as a single species with localized variants. Formal names are not recognized for variants within the species until a biosystematic study of the species complex can be made.
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© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

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Common in rice fields and wet places, 600-1500 m.
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Names and Taxonomy

Taxonomy

The currently accepted scientific name of purple loosestrife is Lythrum salicaria L. (Lythraceae) [57,60,71].

Purple loosestrife will hybridize with
European wand loosestrife (Lythrum virgatum) and winged loosestrife
(Lythrum alatum) [3,92]. A
number of different horticultural cultivars have been developed from purple
loosestrife and wand
loosestrife. Although some are purported to be sterile, crosses within and
between cultivars and wild Lythrum spp. are often compatible, and
identification of cultivars and crosses is problematic [92,118].
  • 57. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. [1168]
  • 118. Skinner, Luke C.; Rendall, William J.; Fuge, Ellen L. 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Special Publication 145. St. Paul, MN: Minnesota Department of Natural Resources, Division of Fish and Wildlife, Ecological Services Section. 27 p. [39783]
  • 3. Anderson, Neil O.; Ascher, Peter D. 1993. Male and female fertility of loosestrife (Lythrum) cultivars. Journal of the American Horticultural Society. 118(6): 851-858. [40318]
  • 92. Ottenbreit, Kimberly A.; Staniforth, Richard J. 1994. Crossability of naturalized and cultivated Lythrum taxa. Canadian Journal of Botany. 72: 337-341. [40288]
  • 60. Kartesz, John T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. 1st ed. In: Kartesz, John T.; Meacham, Christopher A. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Chapel Hill, NC: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy; U.S. Department of Agriculture, Natural Resources Conservation Service; U.S. Department of the Interior, Fish and Wildlife Service. [36715]
  • 71. Larson, Gary E. 1993. Aquatic and wetland vascular plants of the Northern Great Plains. Gen. Tech. Rep. RM-238. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 681 p. Jamestown, ND: Northern Prairie Wildlife Research Center (Producer). Available: http://www.npwrc.usgs.gov/resource/plants/vascplnt/vascplnt.htm [2006, February 11]. [22534]

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Common Names

purple loosestrife

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