History in the United States
Giant reed was probably first introduced into the United States at Los Angeles, California in the early 1800's. Since then, it has become widely dispersed into all of the subtropical and warm temperate areas of the world, mostly through intentional human introductions. Today, giant reed is widely planted throughout the warmer areas of the United States as an ornamental and in the Southwest, where it is used along ditches for erosion control.
Giant reed has a variety of uses ranging from music to medicine. Primitive pipe organs were made from it and the reeds for woodwind instruments are still made from its culms, for which no satisfactory substitutes are known. It is also used in basketry, for fishing rods, livestock fodder, medicine, and soil erosion control.
According to the World Checklist of Selected Plant Families (Board of Trustees of the Royal Botanic Gardens, Kew), this species is native only to a fairly narrow area bounded by Cyprus, Kazakhstan and Turkmenistan in the west, the Gulf States in the south and Japan south to Myanmar in the east. The same source describes it as occurring as an introduction from the Atlantic Ocean island groups and the Iberian Peninsula throughout the Mediterranean south through Africa to South Africa, some of the Indian Ocean island groups, Australia, New Zealand and some Pacific Ocean island groups, as well as North and Central America.
Regularity: Regularly occurring
Global Range: ARUNDO DONAX is a native to the countries surrounding the Mediterranean Sea. From this area it has become widely dispersed, mostly through intentional introduction by man, into all of the subtropical and warm temperate areas of the world.
Mediterranean region eastwards to North Africa, India-Pakistan; introduced into many parts of world
State - Kerala, District/s: Kottayam, Palakkad, Kozhikkode, Thrissur"
Though accounts in the literature vary, a review by Bell  indicates giant reed is thought to be native in eastern Asia, and it has been cultivated throughout Asia, southern Europe, northern Africa and the Middle East for thousands of years. In North America, it was intentionally introduced from the Mediterranean to the Los Angeles area in California in the early 1800s (Robbins and others 1951, as cited in ), and has been widely planted throughout the warmer states as an ornamental and for erosion control along drainage canals [49,74]. It has escaped cultivation as far north as Virginia and Missouri, and abundant wild populations occur along the Rio Grande River  and along ditches, streams, and seeps in arid and cis montane regions of California (Robbins and others 1951, as cited in ).
According to Bell , giant reed is invasive throughout the warmer coastal freshwaters of the United States from Maryland westward to northern California. Wunderlin  recognizes the variety versicolor as occurring in Florida, and Jones and others  describe that variety as a cultivar. The literature contains specific references to the occurrence of giant reed in the 4 provinces of Mexico listed below [2,61,82,98]. Giant reed is likely present in other areas of Mexico.
Plants database provides a state distribution map of giant reed in the United States.
The following lists include North American ecosystems, habitat types, and forest and range cover types in which giant reed is known or thought to be invasive, as well as some that may be invaded by giant reed following disturbances in which vegetation is killed and/or removed and/or soil is disturbed (e.g. cultivation, fire, grazing, herbicide application, flooding). Giant reed is a hydrophyte and riparian areas or wetlands within these habitats could be subject to invasion by giant reed even if the habitat itself is not considered a wetland. For example, Nixon and Willett  list giant reed as a plant found within the Trinity River Basin in Texas. Habitats within the basin include cross timbers and prairies, blackland prairies, post oak (Quercus stellata) savannah, pineywoods, and Gulf prairies and marshes.
These lists are not necessarily exhaustive. More information is needed regarding incidents and examples of particular ecosystems and plant communities where giant reed is invasive.
States or Provinces
Regional Distribution in the Western United States
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 :
3 Southern Pacific Border
4 Sierra Mountains
6 Upper Basin and Range
7 Lower Basin and Range
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
Distribution in the United States
Giant reed is distributed from Arkansas and Texas to California, where it is found throughout the state, and in the east, from Virginia to Kentucky and Missouri and generally southward.
Distribution in Egypt
Nile region, oases, Mediterranean region, Egyptian desert and Sinai.
Mediterranean region, Sinai, eastwards to Myanmar, introduced elsewhere.
The following description of giant reed provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g., [40,53,56,57,62,63,69,77,103,105,107]). Giant reed and common reed, a native grass distributed across most of the United States, can be difficult to distinguish. Proper identification of giant reed is essential before implementing control measures .
Giant reed is a tall, erect, perennial graminoid. It is the largest member of the genus and among the largest of grasses, growing 6 to 30 feet (2-8 m) tall [11,28,74]. The culms reach a diameter of 0.4 to 1.6 inches (1-4 cm) and commonly branch during the second year of growth. Culms are hollow, with walls 2 to 7 mm thick and divided by partitions at the nodes. The nodes vary in length from 5 to 12 inches (12-30 cm). Leaves are conspicuously 2-ranked, 2 to 3.2 inches (5-8 cm) broad at the base and tapering to a fine point. Bases of the leaves are cordate and more-or-less hairy-tufted, persisting long after the blades have fallen . Giant reed has large plume-like panicles. Spikelets are several-flowered with upper florets successively smaller .
Giant reed has thick, knotty rhizomes  and deeply penetrating roots . Once established, it tends to form large, continuous, clonal root masses, sometimes covering several acres. These root masses can be more than 3 feet (1 m) thick (review by ).
Although giant reed has been widely cultivated for centuries, little information on its biology and ecology has been published. As of this writing (2004), more research is needed to understand the biology and ecology of giant reed.
Giant reed, also known as wild cane, is a tall, perennial grass that can grow to over 20 feet in height. Its fleshy, creeping rootstocks form compact masses from which tough, fibrous roots emerge that penetrate deeply into the soil. Leaves are elongate, 1-2 inches wide and a foot long. The flowers are borne in 2-foot long, dense, plume-like panicles during August and September.
Catalog Number: US 78855
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Alleged type specimen status verified from secondary sources
Preparation: Pressed specimen
Collector(s): T. Makino
Locality: Tamsui., Taiwan [Formosa], Taiwan, Asia-Temperate
- Isotype: Hackel, E. 1899. Bull. Herb. Boissier. 7: 724.
Habitat and Ecology
Comments: ARUNDO DONAX has been widely planted throughout the warmer areas of the U.S. as an ornamental. It is especially popular in the Southwest where it is used along ditches for erosion control (Perdue 1958). In California, giant reed has escaped cultivation and has become established in moist places, such as ditches, streams, and seeps in arid and cismontane regions (Robbins et al. 1951). As early as 1820 it was so plentiful along the Los Angeles River that it was gathered for roofing materials (Robbins et al. 1951). A. DONAX tolerates a wide variety of ecological conditions. It is reported to flourish in all types of soils, from heavy clays to loose sands and gravelly soils.
Plants grow best in well-drained soils where abundant moisture is available (Perdue 1958). It can spread from the water's edge up the banks and far beyond the zone previously occupied by riparian woody vegetation (Wells et al. 1980). ARUNDO DONAX was observed to grow well where water tables were close to, or at, the soil surface (Rezk and Edany 1979). Individual plants can tolerate excessive salinity (Perdue 1958).
Giant reed can be seriously retarded by lack of moisture during its first year, but drought causes no great damage to patches two- to three-years old (Perdue 1958). Individuals will survive extended periods of severe drought accompanied by low-pressure humidity or periods of excessive moisture (Perdue 1958). Arundo's ability to tolerate or even grow well under conditions of extreme drought is due to the development of coarse, drought- resistant rhizomes and deeply penetrating roots that can reach moisture at depth. A. DONAX can survive very low temperatures when dormant but is subject to serious damage by frosts after the start of spring growth (Perdue 1958).
Giant reed has played an important role in the culture of the western world through its influence on the development of music, which can be traced back 5000 years. The basis for the origin of the most primitive pipe organ, the Pan pipe or syrinx, was made from A. DONAX. Reeds for woodwind musical instruments are still made from the culms and no satisfactory substitutes have been developed (Perdue 1958).
Even before its musical qualities were appreciated, Egyptians used giant reed as early as 5000 B.C. to line underground grain storage. Mummies of the Fourth Century A.D. were wrapped in arundo leaves. Other uses for giant reed include: basket-work, garden fences and trellises, chicken pens, crude shelters, fishing rods, arrows, erosion control, livestock fodder, pulp and ornamental plants. Medicinally, the rhizome has been used as a sudorific, a diuretic, as an antilactant and in the treatment of dropsy (Perdue 1958).
Although giant reed has a wide distribution in North America, details about site characteristics where it is invasive are limited. Most available information on its biology and ecology in North America comes from reviews and studies in California.
Giant reed is a hydrophyte, and grows best where water tables are near or at the soil surface . Giant reed growth may be retarded by lack of moisture during its first year, but drought causes no serious damage in patches 2 to 3 years old . In California, it typically grows along lakes, streams, drains and other wet sites . It is well adapted for establishment and spread in riparian areas with regular flood cycles (see Asexual regeneration). In California, it is most commonly associated with waterways with altered hydrologic regimes (e.g., dams) and/or disturbed riparian vegetation, but can also establish in the understory of native riparian vegetation . In southern California giant reed reaches peak abundance downstream along major rivers in coastal basins, and has generally not spread up the steep, narrow canyons that characterize lower montane areas . It establishes primarily on streamside microsites, but can spread beyond the zone occupied by native riparian vegetation [24,28,102], and can occur on dry riverbanks far from permanent water . A study along the San Luis Rey River in San Diego County found the highest concentration of giant reed colonies within 24 feet (7.3 m) of the river. The authors suggest frequency and magnitude of river flow contribute to this pattern of distribution .
Giant reed tolerates excessive salinity and periods of excessive moisture . In South Carolina, it has invaded abandoned rice fields and grows in brackish water . In a greenhouse experiment designed to test the tolerance of giant reed to salt stress, Peck  determined giant reed can grow in saline conditions and may be able to invade and persist in salt marshes.
Reviews (e.g., [24,28,49,74]) report that giant reed grows on a variety of soil types including coarse sands, gravelly soil, heavy clays, and river sediments; however, the sources and context of this information are unclear. Stephenson and Calcarone  suggest that it requires "well-developed" soils to become established, while DiTomaso  indicates that giant reed is "best developed in poor, sandy soil and in sunny situations," and survives in areas with pH values between 5 and 8.7. Purdue  states that its growth is most vigorous in well-drained soils where moisture is abundant.
Giant reed occurs in areas with annual precipitation ranging from 12 to 158 inches (300-4,000 mm) . According to Purdue , it is a warm-temperate or subtropical species, and is able to survive very low temperatures when dormant, but is subject to serious damage by frosts that occur after initiation of spring growth.
Elevation ranges reported for giant reed in other areas include:
Habitat: Rangeland Cover Types
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, hardwood, marsh, shrub, vine
SRM (RANGELAND) COVER TYPES :
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
211 Creosote bush scrub
213 Alpine grassland
214 Coastal prairie
215 Valley grassland
216 Montane meadows
401 Basin big sagebrush
402 Mountain big sagebrush
403 Wyoming big sagebrush
405 Black sagebrush
406 Low 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
503 Arizona chaparral
504 Juniper-pinyon pine woodland
505 Grama-tobosa shrub
507 Palo verde-cactus
509 Transition between oak-juniper woodland and mahogany-oak association
601 Bluestem prairie
604 Bluestem-grama prairie
605 Sandsage prairie
611 Blue grama-buffalo grass
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
710 Bluestem prairie
711 Bluestem-sacahuista prairie
712 Galleta-alkali sacaton
715 Grama-buffalo grass
717 Little bluestem-Indiangrass-Texas wintergrass
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
727 Mesquite-buffalo grass
730 Sand shinnery oak
731 Cross timbers-Oklahoma
732 Cross timbers-Texas (little bluestem-post oak)
735 Sideoats grama-sumac-juniper
802 Missouri prairie
803 Missouri glades
804 Tall fescue
806 Gulf Coast salt marsh
807 Gulf Coast fresh marsh
808 Sand pine scrub
809 Mixed hardwood and pine
810 Longleaf pine-turkey oak hills
811 South Florida flatwoods
812 North Florida flatwoods
813 Cutthroat seeps
814 Cabbage palm flatwoods
815 Upland hardwood hammocks
816 Cabbage palm hammocks
817 Oak hammocks
818 Florida salt marsh
819 Freshwater marsh and ponds
820 Everglades flatwoods
821 Pitcher plant bogs
Habitat: Cover Types
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 :
40 Post oak-blackjack oak
42 Bur oak
43 Bear oak
46 Eastern redcedar
51 White pine-chestnut oak
52 White oak-black oak-northern red oak
53 White oak
58 Yellow-poplar-eastern hemlock
59 Yellow-poplar-white oak-northern red oak
60 Beech-sugar maple
61 River birch-sycamore
65 Pin oak-sweetgum
66 Ashe juniper-redberry (Pinchot) juniper
67 Mohrs (shin) oak
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
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
103 Water tupelo-swamp tupelo
104 Sweetbay-swamp tupelo-redbay
105 Tropical hardwoods
110 Black oak
111 South Florida slash pine
221 Red alder
222 Black cottonwood-willow
240 Arizona cypress
241 Western live oak
243 Sierra Nevada mixed conifer
246 California black oak
249 Canyon live oak
250 Blue oak-foothills pine
255 California coast live oak
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
More info for the term: shrub
KUCHLER  PLANT ASSOCIATIONS:
K006 Redwood forest
K009 Pine-cypress forest
K023 Juniper-pinyon woodland
K027 Mesquite bosques
K031 Oak-juniper woodland
K032 Transition between K031 and K037
K034 Montane chaparral
K035 Coastal sagebrush
K036 Mosaic of K030 and K035
K037 Mountain-mahogany-oak scrub
K038 Great Basin sagebrush
K041 Creosote bush
K042 Creosote bush-bur sage
K043 Paloverde-cactus shrub
K044 Creosote bush-tarbush
K045 Ceniza shrub
K048 California steppe
K049 Tule marshes
K053 Grama-galleta steppe
K054 Grama-tobosa prairie
K057 Galleta-threeawn shrubsteppe
K058 Grama-tobosa shrubsteppe
K059 Trans-Pecos shrub savanna
K060 Mesquite savanna
K061 Mesquite-acacia savanna
K062 Mesquite-live oak savanna
K065 Grama-buffalo grass
K069 Bluestem-grama prairie
K070 Sandsage-bluestem prairie
K072 Sea oats prairie
K074 Bluestem prairie
K076 Blackland prairie
K077 Bluestem-sacahuista prairie
K078 Southern cordgrass prairie
K079 Palmetto prairie
K080 Marl everglades
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
K091 Cypress savanna
K098 Northern floodplain forest
K100 Oak-hickory forest
K112 Southern mixed forest
K113 Southern floodplain forest
K115 Sand pine scrub
K116 Subtropical pine forest
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):
FRES12 Longleaf-slash pine
FRES13 Loblolly-shortleaf pine
FRES28 Western hardwoods
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
Habitat in the United States
Giant reed becomes established in moist places such as ditches, streams, and riverbanks, growing best in well drained soils where abundant moisture is available. It tolerates a wide variety of conditions, including high salinity, and can flourish in many soil types from heavy clays to loose sands.
Planted along water-courses, rarely occurring as a native.
Habitat & Distribution
Plant Response to Fire
Immediate Effect of Fire
Fire adaptations: As of this writing (2004), information on fire adaptations of giant reed are limited to anecdotal accounts and assertions based on known biological attributes. Giant reed's extensive rhizomes are likely to survive and sprout after fire removes top growth. Reviews (e.g., [11,28,95]) provide anecdotal evidence that indicates that sprouts emerge from rhizomes of giant reed soon after fire and grow quickly. Rieger and Kreager  observed rapid sprouting and growth of giant reed after removing top-growth by cutting (see Growth).
FIRE REGIMES: With the exception of California, almost no published information is available that describes the types of plant communities in which giant reed is invasive, although giant reed generally occurs in riparian and wetland areas throughout its wide distribution. Characteristics of riparian zones and wetlands vary substantially throughout this range, and FIRE REGIMES are not well described for many of these communities. A review by Dwire and Kauffman  discusses how differences in topography, microclimate, geomorphology, and vegetation may lead to differences in fire behavior and fire effects between riparian areas and surrounding uplands. Riparian areas may act as a fire barrier or a fire corridor, depending on topography, weather, and fuel characteristics . Recovery of riparian vegetation depends on fire severity and postfire hydrology .
Dwire and Kauffman  indicate that riparian microclimates are generally characterized by cooler air temperature, lower daily maximum air temperature, and higher relative humidity than the adjacent uplands, contributing to higher fuel moisture content and presumably lowering the intensity, severity, and frequency of fire in riparian areas compared to adjacent uplands. Similarly, Bell  suggests that fire is uncommon in riparian areas in southern California, and that native riparian species are not well adapted to frequent or severe fire. In this area, lightning-ignited wildfires usually occur in late fall, winter, and early spring when riparian vegetation is typically moist and green and would act as a fire break . In southern California, riparian areas invaded by giant reed often occur within grasslands or chaparral shrublands. The limited available research from such ecosystems suggests longer fire return intervals and lower-severity burns in riparian areas relative to adjacent upland vegetation . Human-caused wildfires often occur during the dry months of the year (July through October) in southern California, when drier conditions make riparian vegetation more vulnerable to fire damage .
Information regarding the effects of giant reed on fuels and fire regime characteristics in plant communities in which it is invasive in North America is limited to accounts from southern California. Although evidence is entirely anecdotal, several accounts (e.g., [11,20,29,84,95]) describe changes in fuels, fire characteristics, and/or postfire plant community response in southern California riparian areas invaded by giant reed that are suggestive of an invasive grass/fire cycle. Because giant reed grows quickly and produces large amounts of biomass  in dense stands described as having "large quantities of dry material" , it is conceivable that its invasion introduces novel fuel properties to the invaded ecosystem. It thus has the potential to alter fire behavior and the fire regime (sensu [14,19]). Giant reed is among the most productive of plant communities and can produce over 20 tons of aboveground biomass per hectare under some conditions . Scott  observes that in the Santa Ana Basin in southern California, the invasion of giant reed into riparian corridors has doubled and in some areas tripled the amount of fuels available for wildfire.
According to Bell [9,11] giant reed is "extremely flammable" throughout most of the year, and once established increases the probability of wildfire occurrence and the intensity of fires that do occur. This observation is upheld by manager and newspaper accounts of intense wildfires fueled by giant reed in Riverside County (as cited in ), the Santa Ana River drainage (J. Wright, personal communication in ), and the Russian River further north . For example, a fire in Soledad Canyon in January 1991 was said to have "burned aggressively through the riparian vegetation" due to dry conditions from a prolonged drought coupled with the presence of dried stands of giant reed (Joyce, personal observation cited in ). Dudley  describes destructive fires fueled by continuous, 15-foot-high colonies of giant reed along the Santa Ana River, noting that "such flammable vegetation is now changing riparian corridors from barriers to the spread of fires into wicks that carry fire up and downstream, into highway bridges or crowns of native, fire-sensitive trees". See Fire hazard potential for more information on this topic.
As of this writing (2004) no research is available on postfire response of giant reed; however, observations indicate that in most circumstances fire cannot kill the underground rhizomes and probably favors giant reed regeneration over native riparian species (e.g., Gaffney and Cushman 1998, cited in ). One week after a fire in Soledad Canyon in January 1991, for example, burned giant reed colonies were sprouting from their extensive rhizomes. Many sprouts were over 2 feet (0.6 m) tall within 2 weeks after the fire, even though January is normally the dormant period for giant reed. Most willow, mulefat, and aquatic plants were also burned, and many cottonwoods were scorched. The aquatic plants in the stream were the only plants other than giant reed that were recovering within the first few weeks of burning. In this way, fire gives giant reed an advantage over native riparian plants, and its dominance in the area has increased dramatically (Joyce, personal observation in ). In this sense, Bell  suggests that riparian communities invaded by giant reed can change from "flood-defined" to "fire-defined" communities, as has occurred on the Santa Ana River. This grass/fire cycle would thus result in river corridors dominated by stands of giant reed with little biological diversity .
As mentioned above, there is little research regarding FIRE REGIMES and fire return intervals in riparian areas. However, riparian communities may be influenced by the FIRE REGIMES of adjacent and surrounding plant communities. The following table provides fire return intervals for plant communities and ecosystems where riparian vegetation may include giant reed, though its invasiveness in many of these communities has not yet been demonstrated. For further information on FIRE REGIMES in these communities, see the FEIS summary on the dominant species listed below.
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|silver maple-American elm||Acer saccharinum-Ulmus americana||< 35 to 200|
|sugar maple||Acer saccharum||> 1,000|
|sugar maple-basswood||Acer saccharum-Tilia americana||> 1,000 |
|California chaparral||Adenostoma and/or Arctostaphylos spp.||72]|
|bluestem prairie||Andropogon gerardii var. gerardii-Schizachyrium scoparium||59,72]|
|Nebraska sandhills prairie||Andropogon gerardii var. paucipilus-Schizachyrium scoparium||< 10|
|bluestem-Sacahuista prairie||Andropogon littoralis-Spartina spartinae||72]|
|silver sagebrush steppe||Artemisia cana||5-45 [46,76,106]|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||Artemisia tridentata var. tridentata||12-43 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [5,16,66]|
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (40**) [100,109]|
|coastal sagebrush||Artemisia californica||< 35 to < 100|
|saltbush-greasewood||Atriplex confertifolia-Sarcobatus vermiculatus||72]|
|mangrove||Avicennia nitida-Rhizophora mangle||35-200 |
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||5-100 |
|plains grasslands||Bouteloua spp.||< 35|
|blue grama-buffalo grass||Bouteloua gracilis-Buchloe dactyloides||72,106]|
|grama-galleta steppe||Bouteloua gracilis-Pleuraphis jamesii||< 35 to < 100|
|blue grama-tobosa prairie||Bouteloua gracilis-Pleuraphis mutica||72]|
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|sugarberry-America elm-green ash||Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica||101]|
|paloverde-cactus shrub||Cercidium microphyllum/Opuntia spp.||72]|
|curlleaf mountain-mahogany*||Cercocarpus ledifolius||13-1,000 [6,83]|
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii||72]|
|Atlantic white-cedar||Chamaecyparis thyoides||35 to > 200 |
|blackbrush||Coleogyne ramosissima||< 35 to < 100|
|Arizona cypress||Cupressus arizonica||< 35 to 200|
|northern cordgrass prairie||Distichlis spicata-Spartina spp.||1-3 |
|beech-sugar maple||Fagus spp.-Acer saccharum||> 1,000 |
|California steppe||Festuca-Danthonia spp.||72,89]|
|black ash||Fraxinus nigra||101]|
|juniper-oak savanna||Juniperus ashei-Quercus virginiana||< 35|
|Ashe juniper||Juniperus ashei||< 35|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||Juniperus scopulorum||72]|
|cedar glades||Juniperus virginiana||3-22 [43,72]|
|creosotebush||Larrea tridentata||< 35 to < 100|
|Ceniza shrub||Larrea tridentata-Leucophyllum frutescens-Prosopis glandulosa||72]|
|Everglades||Mariscus jamaicensis||< 10|
|wheatgrass plains grasslands||Pascopyrum smithii||72,76,106]|
|southeastern spruce-fir||Picea-Abies spp.||35 to > 200 |
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to > 200|
|pine-cypress forest||Pinus-Cupressus spp.||4]|
|Mexican pinyon||Pinus cembroides||20-70 [67,92]|
|shortleaf pine||Pinus echinata||2-15|
|shortleaf pine-oak||Pinus echinata-Quercus spp.||101]|
|Colorado pinyon||Pinus edulis||10-400+ [36,41,58,72]|
|slash pine||Pinus elliottii||3-8|
|slash pine-hardwood||Pinus elliottii-variable||< 35|
|sand pine||Pinus elliottii var. elliottii||25-45 |
|South Florida slash pine||Pinus elliottii var. densa||1-5|
|longleaf-slash pine||Pinus palustris-P. elliottii||1-4 [70,101]|
|longleaf pine-scrub oak||Pinus palustris-Quercus spp.||6-10 |
|pitch pine||Pinus rigida||6-25 [15,44]|
|pond pine||Pinus serotina||3-8|
|eastern white pine||Pinus strobus||35-200|
|eastern white pine-eastern hemlock||Pinus strobus-Tsuga canadensis||35-200|
|loblolly pine||Pinus taeda||3-8|
|loblolly-shortleaf pine||Pinus taeda-P. echinata||10 to < 35|
|Virginia pine||Pinus virginiana||10 to < 35|
|Virginia pine-oak||Pinus virginiana-Quercus spp.||10 to < 35|
|sycamore-sweetgum-American elm||Platanus occidentalis-Liquidambar styraciflua-Ulmus americana||101]|
|galleta-threeawn shrubsteppe||Pleuraphis jamesii-Aristida purpurea||< 35 to < 100|
|eastern cottonwood||Populus deltoides||72]|
|mesquite-buffalo grass||Prosopis glandulosa-Buchloe dactyloides||< 35|
|Texas savanna||Prosopis glandulosa var. glandulosa||72]|
|mountain grasslands||Pseudoroegneria spicata||3-40 (10**) [3,4]|
|California oakwoods||Quercus spp.||4]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||72]|
|oak-gum-cypress||Quercus-Nyssa-spp.-Taxodium distichum||35 to > 200 |
|southeastern oak-pine||Quercus-Pinus spp.||101]|
|coast live oak||Quercus agrifolia||2-75 |
|white oak-black oak-northern red oak||Quercus alba-Q. velutina-Q. rubra||101]|
|canyon live oak||Quercus chrysolepis||<35 to 200|
|blue oak-foothills pine||Quercus douglasii-P. sabiniana||4]|
|northern pin oak||Quercus ellipsoidalis||101]|
|Oregon white oak||Quercus garryana||4]|
|bear oak||Quercus ilicifolia||101]|
|California black oak||Quercus kelloggii||5-30 |
|bur oak||Quercus macrocarpa||101]|
|oak savanna||Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium||2-14 [72,101]|
|chestnut oak||Quercus prinus||3-8|
|post oak-blackjack oak||Quercus stellata-Q. marilandica||< 10|
|black oak||Quercus velutina||< 35|
|live oak||Quercus virginiana||10 to101]|
|interior live oak||Quercus wislizenii||4]|
|cabbage palmetto-slash pine||Sabal palmetto-Pinus elliottii||70,101]|
|blackland prairie||Schizachyrium scoparium-Nassella leucotricha||< 10|
|Fayette prairie||Schizachyrium scoparium-Buchloe dactyloides||101]|
|little bluestem-grama prairie||Schizachyrium scoparium-Bouteloua spp.||< 35|
|tule marshes||Scirpus and/or Typha spp.||72]|
|redwood||Sequoia sempervirens||5-200 [4,35,90]|
|southern cordgrass prairie||Spartina alterniflora||1-3 |
|baldcypress||Taxodium distichum var. distichum||100 to > 300|
|pondcypress||Taxodium distichum var. nutans||70]|
|eastern hemlock-yellow birch||Tsuga canadensis-Betula alleghaniensis||> 200 |
|western hemlock-Sitka spruce||Tsuga heterophylla-Picea sitchensis||> 200 |
More info for the terms: fire regime, grass/fire cycle, top-kill
Giant reed can establish and spread in communities of various successional stages, acting as an early-successional pioneer species, and a late-successional dominant.
According to reviews by Bell  and Dudley , giant reed is well adapted to the high disturbance dynamics of riparian systems, as floods break up clumps of giant reed and spread pieces downstream where they can take root and establish new clones. In California, it is most common along waterways with altered hydrologic regimes (e.g., dams) and/or disturbed riparian vegetation, but can also establish in the understory of native riparian vegetation . However, establishment of giant reed in dense, mature riparian vegetation may be limited .
Once established, giant reed grows quickly [74,80] and spreads vegetatively, often forming monocultural stands that physically inhibit growth of other plant species [11,26,80]. Invaded habitats may thus become pure stands of giant reed [10,80,95].
Although evidence is limited and anecdotal, some authors (e.g., [9,84]) note changes in fuels, fire characteristics, and postfire plant community response that are suggestive of an invasive grass/fire cycle perpetuated by giant reed invasion in southern California riparian areas. Because giant reed produces abundant biomass (i.e., fuel), is "extremely flammable", and responds with rapid growth from sprouting rhizomes after top-kill, it may alter fire regime characteristics and successional processes of invaded riparian ecosystems (see FIRE REGIMES).
The reproductive biology of giant reed is not well studied. As of this writing (2004), information on the importance of sexual reproduction, seed viability, dormancy, germination and seedling establishment is not available.
Breeding system: No information is available on this topic.
Pollination: No information is available on this topic.
Seed dispersal: The hairy, light-weight disseminules (individual florets with the enclosed grain) are dispersed by wind .
Seed banking: No information is available on this topic.
Germination: No information is available on this topic.
Seedling establishment/growth: Seedlings of giant reed have not been observed in the field . Establishment of giant reed is from fragmented rhizomes or stem nodes that take root (see Asexual regeneration, below).
Giant reed grows very rapidly. In a southern California study, Rieger and Kreager  cut an established giant reed community and measured its growth after cutting. Growth rates from established rhizomes averaged 2.5 inches (6.25 cm) per day in the first 40 days and 1 inch (2.67 cm) per day in the first 150 days. Under optimal conditions (i.e., cultivation) giant reed is reported to grow 1.5 to 4 inches (4-10 cm) per day (review by ).
Asexual regeneration: Population expansion of giant reed in North America is through vegetative reproduction. This occurs either via underground rhizome extension or from plant fragments carried downstream (review by ). Giant reed is well adapted to the high disturbance dynamics of riparian systems, as floods break up clumps of giant reed and spread pieces downstream where they can take root and establish new clones [11,28]. Anecdotal accounts suggest that rhizomes buried under as much as 3 to 10 feet (1-3 m) of alluvium can "readily resprout" (R. Dale, personal communication in ).
Much of the cultivation of giant reed throughout the world is initiated by planting rhizomes which root and sprout easily [48,49]. A 1949 joint publication by the U.S. Forest Service and the California Department of Natural Resources, Division of Forestry, describing recommended plants for erosion control  states pieces of giant reed rhizomes can be buried to establish the plant. A 1988 paper describes giant reed as a planted rhizome which "performs well" as an understory plant in riparian zones in New Mexico . In a greenhouse experiment, Motamed  determined that giant reed stem fragments rooted throughout the growing season.
Growth Form (according to Raunkiær Life-form classification)
Life History and Behavior
More info for the term: phenology
Information on the phenology of giant reed in the literature is sparse. In California, culms may remain green throughout the year, but can fade during semi-dormancy during the winter months or in drought [28,99]. According to Bell  in an assessment of optimal timing of herbicide application, giant reed plants actively translocate nutrients to the rootmass in preparation for winter dormancy around mid-August to early November.
|Flowering dates for giant reed by location|
|Time of flowering|
|California (southern)||late summer |
|Carolina, North and South||September-October |
|Florida||all year |
|New Mexico||June to September |
Very little information is available in the literature regarding the biology of A. DONAX.
Perdue (1958) reports that arundo does not produce viable seeds in most areas where it is apparently well-adapted, although plants have been grown in scattered locations from seed collected in Asia.
Wind dispersal of seeds is facilitated by having a dense seed head on the end of a tall, flexible culm, presumably catapulting the seeds a fair distance. The importance of sexual reproduction to the species, as well as seed viability, dormancy, germination and seedling establishment, have yet to be studied and published.
Much of the cultivation of arundo throughout the world is initiated by planting rhizomes which root and sprout readily. Wild stands in the U.S. have been reported to yield 8.3 tons of oven-dry cane per acre (Perdue 1958).
Giant reed grows rapidly. Growth rates up to 0.7 meters/week over a period of several months under favorable conditions is not unusual. Young culms develop the full diameter of mature canes; further growth involves thickening of the walls. The new growth is soft, very high in moisture and has little wind resistance (Perdue 1958).
Biology and Spread
Reproduction of giant reed is primarily vegetative, through rhizomes which root and sprout readily. Little is known about the importance of sexual reproduction in giant reed, or about its seed viability, dormancy, and germination, and seedling establishment. Research on these topics may yield some additional improvements in the management of giant reed.
Molecular Biology and Genetics
Barcode data: Arundo donax
Statistics of barcoding coverage: Arundo donax
Public Records: 8
Specimens with Barcodes: 19
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
This species is assessed as Least Concern because it is widespread and does not face any major threats.
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Global Short Term Trend: Increase of 10 to >25%
There are no known significant past, ongoing or future threats to this species.
Comments: Arundo can rapidly invade streambanks and roadside habitats from a few planted individuals. When established, it has a strong ability to outcompete and completely suppress native vegetation. Because it propagates vegetatively, it can form rather pure stands, often at the expense of other plants (Wells et al. 1980). In some areas it may so totally invade irrigation ditches as to reduce their water-carrying capacity (Robbins et al. 1951).
A survey of 48 public agencies listed arundo as one of the top 53 weed species of concern (Armer 1964). Arundo was nominated for Element Stewardship Abstract research by preserve managers from Santa Rosa Plateau and Creighton Ranch.
There are no conservation measures in place and none needed.
Restoration Potential: With proper management, areas infested with arundo may be restored to more desirable vegetation. Since arundo may be spread primarily by dispersal of rhizome fragments along watercourses, removal of the entire rootstock may be adequate to eradicate the plant. Research is needed to determine the importance of sexual reproduction in this species.
Management Requirements: Weed control involves three fundamental objectives: prevention, eradication and control.
From a practical viewpoint, methods of weed management are commonly categorized under the following categories: physical, thermal, managerial, biological, and chemical (Watson 1977). Physical methods include both manual and mechanical methods. Thermal methods include both broadcast burning or spot treatment with a flame thrower. Managerial methods include the encouragement of competitive displacement by native plants and prescribed grazing. Biological control is usually interpreted as the introduction of insects or pathogens which are highly selective for a particular weed species. Chemical control includes both broadcast and spot application.
The most desirable approach is that of an integrated pest management plan. This involves the optimum use of all control strategies to control weeds. This approach is generally accepted as the most effective, economical, and environmentally sound long- term pest control strategy (Watson 1977). In cases where more than one control technique is used, the various techniques should be compatible with one another. Broadcast herbicide application, for example, may not work well with certain managerial techniques (i.e., plant competition).
PHYSICAL CONTROL The two types of physical control methods discussed below, manual and mechanical, produce slash debris that can be disposed of by several techniques. If cut before seeds are produced, debris may be piled and left for enhancement of wildlife habitat (i.e., cover for small mammals). Debris may be fed through a mechanical chipper and used as mulch during revegetation procedures. Care should be taken to prevent vegetative reproduction from cuttings. Burning the slash piles is also effective in disposing of slash.
MANUAL CONTROL Manual methods use hand labor to remove undesirable vegetation. These methods are highly selective and permit weeds to be removed without damage to surrounding native vegetation.
The Bradley Method is one sensible approach to manual control of weeds (Fuller and Barbe 1985). This method consists of hand weeding selected small areas of infestation in a specific sequence, starting with the best stands of native vegetation (those with the least extent of weed infestation) and working towards those stands with the worst weed infestation. Initially, weeds that occur singly or in small groups should be eliminated from the extreme edges of the infestation. The next areas to work on are those with a ratio of at least two natives to every weed. As the native plant stabilizes in each cleared area, work deeper into the center of the most dense weed patches. This method has great promise on nature reserves with low budgets and with sensitive plant populations. More detailed information is contained in Fuller and Barbe (1985).
Hand Pulling: This method may be used to destroy seedlings or plants up to two meters tall. Plants or seedlings are best pulled after a rain when the soil is loose. This facilitates removal of the rooting system, which may resprout if left in the ground. Plants should be pulled as soon as they are large enough to grasp but before they produce seeds.
Hand Digging: The removal of rootstocks by hand digging is a slow but sure way of destroying weeds which resprout from their roots. The work must be thorough to be effective. Every piece of root that breaks off and remains in the soil may produce a new plant. Such a technique is only suitable for small infestations or around trees and shrubs where other methods are not practical.
MECHANICAL CONTROL Mechanical methods use mechanized equipment to remove above ground vegetation. These methods are often non-selective in that all vegetation on a treated site is affected. Mechanical control is highly effective at controlling woody vegetation on gentle topography with few site obstacles. Most mechanical equipment is not safe to operate on slopes over 30 percent. It is also of limited use where soils are highly susceptible to compaction or erosion or where excessive soil moisture is present. Site obstacles such as rocks, stumps or logs also reduce efficiency.
Chopping, Cutting or Mowing: ARUNDO DONAX may be trimmed back by tractor-mounted mowers on even ground or by scythes on rough or stony ground. Unwanted vegetation can be removed faster and more economically in these ways than by manual means and with less soil disturbance than with scarification. However, these methods are non-selective weed eradication techniques. They reduce biological control potential (other plants outcompeting arundo) and may open up new niches for undesirable vegetation. In addition, wildlife forage is eliminated. Another disadvantage of chopping, cutting or mowing is that perennial weeds usually require several cuttings before the underground parts exhaust their reserve food supply. If only a single cutting can be made, the best time is when the plants begin to flower. At this stage the reserve food supply in the roots has been nearly exhausted, and new seeds have not yet been produced.
PRESCRIBED BURNING Flame Thrower: A flame thrower or weed burner device can be used as a spot treatment to heat-girdle the stems at the base of arundo plants. This technique has advantages of being less costly than basal and stem herbicide treatments and is suitable for use during wet weather; it cannot be used during periods of wildfire hazard. Its effectiveness is comparable to manual cutting. The timing of the treatment may affect resprouting behavior (Jones and Stokes Associates 1984).
Broadcast Burning: Large areas of weed infestation may be burned in order to remove the standing mature plants. This may be accomplished with or without a pre-spray of herbicides to kill and desiccate plants, Notably flammable plants usually do not require any pre-spray treatment. Used alone this method will not prevent resprouting from root crowns. Burning is best followed by 1) herbicide treatment of stumps, 2) subsequent burning to exhaust soil seed bank and underground food reserves, and/or 3) revegetation with fast growing native species. Other considera- tions for the use of prescribed burning include the time and cost of coordinating a burn, and the soil disturbance resulting from firebreak construction.
MANAGERIAL CONTROL Prescribed grazing: Giant reed is not very palatable to cattle, but during the drier seasons the animals do not hesitate to graze this species. The younger shoots are eaten first, followed by the upper parts of the older plants (Wynd et al. 1948).
In many areas of California the use of Angora and Spanish goats is showing promise as an effective control for ARUNDO DONAX (Daar 1983). In the Cleveland National Forest goats are herded for firebreak management of brush species on over 79,000 acres of land. Goats are less costly to utilize than mechanical and chemical control methods. They can negotiate slopes too steep to manage with machines and do not pose the environmental dangers inherent with herbicides (Andres 1979).
A pioneer in the use of goats for weed control in urban settings is Richard Otterstad, owner of Otterstad's Brush Clearing Service (718 Adams St., Albany, CA 94706, (415) 524-4063). The primary weed control "tools" utilized by Otterstad's company are Angora goats and light-weight flexible fencing reinforced with electrified wire. Angora's are preferred over Spanish goats because their smaller size makes them easier to transport (Otterstad uses a pickup truck). Dairy goats were abandoned when Otterstad found them to be "goof-offs" when it came to eating (Daar 1983).
Goats prefer woody vegetation over most grasses or forbs; Angoras have a higher tolerance for non-woody species than do Spanish goats. Since goats will trample or browse virtually any vegetation within a fenced area, any desirable trees or shrubs must be protected.
Sheep are more selective than goats in their food choices but function well in grazing down a variety of plants. Sheep in feeding experiments may survive for extended periods on a strict diet of ARUNDO DONAX (Frattegglani-Bianchi 1963), thus sheep may be another practical alternative to mowing.
It is important to properly manage sheep grazing to prevent soil compaction problems which may occur when sheep are allowed to graze an overly damp area. Sheep are valuable not only for weed control but also for additional income from the sale of their wool and their contribution of fertilizer to the soil. However, it is possible that seed re-introduction may occur from the sheep droppings.
Geese, especially the more wild breeds, are known to be very active and effective weeders of grass and sedges (Andres 1979). This suggests that making an area attractive to waterfowl might contribute to arundo control efforts.
BIOLOGICAL CONTROL The term "biological control" is used here to refer to the use of insects or pathogens to control weeds. The introduction of exotic natural enemies to control plants is a complex process and must be thoroughly researched before implementation to prevent biological disasters. Such tools are not normally suitable for preserve managers to implement.
Little is known about the actual effects of various pathogens and insects on the growth and reproduction of A. DONAX. However, numerous insects are known to feed on this species. The green bug (SCHIZAPHIZ GRAMINUM) has been observed to feed on arundo during the winter (Zuniga et al. 1983). In France PHOTHEDES DULCIS caterpillars may feed on it (Dufay 1979). ZYGINIDIA GUYUMI uses A. DONAX as an important food source in Pakistan (Ahmed et al. 1977). A moth borer (DIATRAEA SACCHARALIS) has been reported to attack it in Barbados (Tucker 1940). Although these insects may eventually prove to be effective in controlling arundo, it is unlikely that insects or pathogens will be introduced as controlling agents because arundo is widely cultivated as a commercial crop.
Please notify the California Field Office of The Nature Conser- vancy of any field observations in which a native insect or pathogen is seen to have detrimental effects on arundo. These reports will be used to update this Element Stewardship Abstract. Management techniques which may encourage the spread of such species-specific agents may be desirable in controlling arundo.
CHEMICAL CONTROL Detailed information on herbicides are available in such publica- tions as Weed Science Society of America (1983) or USDA (1984), and will not be comprehensively covered here. The Weed Science Society publication gives specific information on nomenclature, chemical and physical properties of the pure chemical, use recommendations and precautions, physiological and biochemical behavior, behavior in or on soils and toxological properties for several hundred chemicals. In applying herbicides it is recommended that a dye be used in the chemical mixture to mark the treated plants and thus minimize waste.
Dowpon-C-grass-killer, based on sodium salts of dalapon and TCA, is applied as a full coverage foliar spray to control deep rooted perennial grasses. Arnold and Warren (1966) used it at a rate of 15 pounds per 100 gallons (plus 2 quarts of surfactant) in late spring and summer on A. DONAX. This rate gave good top growth kill in 2 to 4 weeks. A small amount of regrowth was evident in 6 months. Fall applications at the same rates resulted in no regrowth the following spring. Horng and Leu (1979) studied the effects of several herbicides on arundo in Taiwan. Glyphosate at 2-3 kg/ha showed slow control, effecting over 95% kill 3 months after application. 2,2 DPA at 6-8 kg/ha gave 80% kill within 25 days. Following either glyphosate or 2,2 DPA application with doses of paraquat showed much faster and more complete control. Paraquat alone at 0.72 kg/ha effectively controlled arundo. Two applications of paraquat was just as effective as a single application. Asulam did not adequately control A. DONAX.
Monitoring Programs: No quantitative monitoring studies of arundo were discovered in this research.
Management Research Needs: What are the most appropriate means of controlling arundo in riparian areas with minimal disturbance to the surrounding native vegetation?
Biological Research Needs: Much more information on seed biology, seedling establishment, growth patterns, and synecology needs to be gathered about arundo.
Of great interest is the importance of sexual reproduction over vegetative propagation in the establishment of the plant in new locations. Does arundo produce viable seed in California?
Impacts and Control
Impacts: Bell  considers giant reed to be the greatest threat to southern California's remaining riparian corridors. It is so widespread and problematic in this area that more than 20 public and private organizations came together to form the Santa Ana River Arundo Management Task Force, also known as Team Arundo .
Once established, giant reed often forms monocultural stands that physically inhibit growth of other plant species [11,80]. For example, Douthit  describes a 1993 preliminary riparian assessment of the Santa Ana River basin where in the Riverside West Quad, 762 acres (308 ha) of 1,116 acres (470 ha) of riparian vegetation are impacted by giant reed. Of the impacted acres, 535 acres (217 ha) are monospecific stands of giant reed.
Although evidence is entirely anecdotal, several accounts (e.g., [11,20,29,84,95]) describe changes in fuels, fire characteristics, and/or postfire plant community response in southern California riparian areas invaded by giant reed that are suggestive of an invasive grass/fire cycle. The result of such cycle is loss of native riparian species, and continued dominance and spread of giant reed. See Fire ecology for more details.
Canopy structure of giant reed colonies differs from that of native vegetation, resulting in changes in water quality and wildlife habitat. The lack of stream-side canopy structure may result in increased pH in the shallower sections of rivers due to high algal photosynthetic activity [9,17]. In turn, high pH facilitates conversion of ammonium (NH4+) to toxic ammonia (NH3), which further degrades water quality for aquatic species and for downstream users . Several species listed as endangered are further threatened by giant reed invasion and control efforts in San Francisquito Canyon including least Bell's vireo, unarmored threespine stickleback, and Nevin's barberry (Mahonia nevinii) .
Giant reed is becoming a major biological pollutant of river estuaries and beaches. It is often ripped out of the soft bottoms of rivers during storms and washed downstream into flood control channels . Giant reed growing in flood control channels necessitates constant removal. It can form debris dams against flood control and transportation structures such as bridges and culverts [29,37]. Because the rhizomes of giant reed grow close to the surface, they break off during floods. When the root mass breaks away during these floods the riverbanks are destabilized. Destabilization of riverbanks is the leading cause of flooding in southern California .
Iverson  provides insight into the economics of giant reed's impact on water use. He estimates giant reed transpires 56,200 acre-feet of water per year on the Santa Ana River, compared to an estimated 18,700 acre-feet that would be consumed by native vegetation - the difference being enough water to serve a population of about 190,000 people. If that amount of untreated water (37,500 acre-feet) was purchased from the Metropolitan Water Association it would cost approximately $12,000,000 in 1993 dollars .
Control: A suite of methods is needed to control giant reed depending on presence or absence of native plants, size of the stand, amount of biomass involved, terrain, and season. The key to effective treatment of established giant reed is killing or removing the rhizomes .
To be successful, a program to eliminate a riparian invasive plant like giant reed must start at the uppermost reaches of the watershed and work down stream. This means there must be coordination with all of the landowners and land managers, top to bottom, in a watershed. Regulatory agencies must provide technical assistance and required permits, and private landowners must provide work crews access to land .
To adequately coordinate removal of giant reed in a watershed, 3 programs need to be operating: 1) create a functional mapped database that contains hydrology, land ownership/use, infestations, project sites, etc.; 2) coordination with regulatory agencies to plan mitigation project sites to fit within other current projects; 3) regular meetings of stakeholders to share information regarding threats from giant reed, control techniques, funding opportunities, and each stakeholder's direct role and responsibility .
Prevention: Grading and construction can spread giant reed . Care must therefore be taken in areas where it occurs such that soil disturbance and movement of plant parts is minimized.
Integrated management: A popular approach to treating giant reed has been to cut the stalks and remove the biomass, wait 3 to 6 weeks for the plants to grow about 3.3 feet (1 m) tall, then apply a foliar spray of herbicide solution. The chief advantage to this approach is less herbicide is needed to treat fresh growth compared with tall, established plants, and coverage is often better because of the shorter and uniform-height plants. However, cutting the stems may result in plants returning to growth-phase, drawing nutrients from the root mass. As a result there is less translocation of herbicide to the roots and less root-kill. Additionally, cut-stem treatment requires more time and personnel than foliar spraying and requires careful timing. Cut stems must be treated with concentrated herbicide within 1 to 2 minutes of cutting to ensure tissue uptake. This treatment is most effective after flowering. The advantage of this treatment is that it requires less herbicide and the herbicide can be applied more precisely. It is rarely less expensive than foliar spraying except on very small, isolated patches or individual plants .
An investigation to test the effectiveness of glyphosate for control of giant reed was conducted in southern California by Caltrans, the state transportation agency. Results indicate cut-stem treatments, regardless of time of application (May, July, or September), provided 100% control with no resprouting. In contrast, virtually all plants that were left untreated following cutting resprouted vigorously. Foliar treatments produced highly variable results with top die-back varying from 10 to 90% and resprouting ranging from 0 to 100% at various sites. The authors conclude treatment of cut stems appears more effective than foliar spraying in controlling giant reed with glyphosate .
In 1995, a full-scale project for control of giant reed was initiated in San Francisquito Canyon in the Angeles National Forest. The standing giant reed was mulched in place, using a hammer flail mower attached to a tractor, and then glyphosate was applied to the resprouts. Initial mulching occurred in October and November, 1995. Resprouts in spring, 1996, were treated with a solution of glyphosate in April, May, July, and August. Resprouts were treated again in June and September, 1997. In 1998, giant reed continued to resprout in the treatment area, but comprised only 1% of vegetative cover, as compared to 30% to 80% prior to treatment . No information is provided about the composition of the plant community posttreatment.
Physical/mechanical: Minor infestations of giant reed can be eradicated by manual methods, especially where sensitive native plants and wildlife might be damaged by other methods. Hand pulling works with new plants less than 6.6 feet (2 m) in height, but care must be taken that all rhizomes are removed . This may be most effective in loose soils and after rains have loosened the substrate. Giant reed can be dug using hand tools and in combination with cutting plants near the base. Stems and roots should be removed and burned on site to prevent rerooting. The fibrous nature of giant reed makes using a chipper difficult (R. Dale personal communication in ). For larger infestations on accessible terrain, heavier tools (rotary brush cutter, chainsaw, or tractor-mounted mower) may facilitate biomass removal followed by rhizome removal or chemical treatment. Such methods may be of limited value on complex or sensitive terrain or on slopes over 30%. These methods may also interfere with re-establishment of native plants . Mechanical eradication of giant reed is extremely difficult, even with the use of a backhoe, as rhizomes buried under 3 to 10 feet (1-3 m) of alluvium readily resprout (R. Dale personal communication in ).
Cut material is often burned on site, subject to local fire regulations, because of the difficulty and expense involved in collecting and removing or chipping all material. Stems and roots must be removed, chipped, or burned on site to avoid re-rooting (Dale, personal communication in ).
Fire: See Fire Management Considerations.
Biological: Tracy and DeLoach  provide an exhaustive summary of the search for biological control agents for giant reed in the United States. Areas dominated by giant reed in North America are essentially devoid of wildlife. This means native flora and fauna do not offer any significant control potential . It is uncertain what natural controlling mechanisms for giant reed are in its countries of origin, although corn borers (Eizaguirre and others 1990 in ), spider mites , and aphids  have been reported in the Mediterranean. A sugar cane moth-borer in Barbados is reported to attack giant reed, but it is also a major pest of sugar cane and is already found in the United States in Texas, Louisiana, Mississippi, and Florida . A leafhopper in Pakistan utilizes giant reed as an alternate host but attacks corn and wheat .
In the United States a number of diseases have been reported on giant reed, including root rot, lesions, crown rust, and stem speckle, but none seem to have seriously impacted advance of this weed .
Giant reed is not very palatable to cattle, but during the drier seasons they will graze the young shoots, followed by the upper parts of the older plants . In many areas of California the use of Angora and Spanish goats is showing promise for controlling giant reed .
Chemical: Application of herbicides on giant reed is most effective after flowering and before dormancy. During this period, usually mid-August to early November in southern California, the plants are actively translocating nutrients to the root mass in preparation for winter dormancy. This may result in effective translocation of herbicide to the roots . Comparison trials on the Santa Margarita River in southern California indicate foliar application during the appropriate season results in almost 100% control, compared with only 5 to 50% control using cut-stem treatment. Two to 3 weeks after foliar treatment the leaves and stalks brown and soften creating an additional advantage in dealing with the biomass. Cut green stems might take root if left on damp soil and are very difficult to cut and chip. Treated stems have little or no potential to root and are brittle (Omori 1996 in Bell ). Bell , Hoshovsky , and Jackson  provide detailed information on specific herbicides and concentrations used to treat giant reed.
In the proceedings from a workshop on giant reed control published online, Bell  asserts pure stands of giant reed (>80% canopy cover) are most efficiently and effectively treated by aerial application of an herbicide concentrate, usually by helicopter. Helicopter application can treat at least 124 acres (50 ha) per day. In areas where helicopter access is impossible and giant reed makes up the understory, where patches are too small to make aerial application financially efficient, or where giant reed is mixed with native plants (<80% canopy coverage), herbicides must be applied by hand.Cultural: Giant reed appears to be insensitive to flood regime. It survives and spreads through vegetative propagation during long periods without flooding but spreads during flood events as well. Because it does not reproduce sexually, giant reed is not affected by the timing of spring flows, but can establish any time that flood flows carry and deposit stem fragments or rhizomes. It thrives along edges of reservoirs, irrigation canals, and other structures where timing of drawdowns is incompatible with maintenance of native species .
Conversely, native riparian species and communities depend on natural flood regimes for maintenance and reproduction. If natural flood dynamics are maintained as part of an integrated management approach, native species may have a better chance of competing with giant reed in the long term .
Relevance to Humans and Ecosystems
Uses: FIBER, Building materials/timber, LANDSCAPING, Cultivated ornamental, Erosion control
Other uses and values
Giant reed has been planted extensively for erosion control along drainage canals . Wynd and others  report it can also be used to stabilize sand dunes. It is also used for thatching roofs of sheds, barns and other buildings . Mexican campesinos use new tillers of giant reed for roofing and construction materials. It is the most important construction material in the Juamave region of Mexico . Giant reed makes a good quality paper, and in Italy it is used in the manufacture of rayon .
Giant reed is used to make reeds for a variety of musical instruments including bagpipes [11,74]. Reeds for woodwind musical instruments are still made from the culms of giant reed, and no satisfactory substitutes have been developed. The basis for the origin of the most primitive pipe organ, the Pan pipe or syrinx, was made from giant reed .
Five thousand years ago Egyptians used giant reed to line underground grain storage bins, and mummies from the 4th century A.D. were wrapped in giant reed leaves. Additional uses include basket-making, fishing rods, arrows, and ornamental plants. Medicinally, giant reed's rhizome has been used as a sudorific, a diuretic, an antilactant, and in the treatment of dropsy .
Importance to Livestock and Wildlife
Available evidence indicates giant reed provides neither food nor habitat for native species of wildlife . Bell  speculates that insects are sparse in sites dominated by giant reed because of abundant chemical defense compounds produced by the plant.
Palatability/nutritional value: Giant reed stems and leaves contain a wide array of chemicals that probably protect it from most native insects and grazers. These chemicals include silica [51,74], triterpines, sterols , cardiac glycosides, curare-mimicking indoles , hydroxamic acid, and numerous other alkaloids (Bell  and references therein).
Nutritional content of giant reed. Results are an average of 2 samples for each category and are presented as percentages of oven-dry weight :
|Old plant||Young plant|
|Lower half||Upper half||Lower half||Upper half|
|Protein (total N x 6.25)||3.94||6.88||3.13||12.25|
Cover value: Areas dominated by giant reed are largely depauperate of wildlife [9,11,54]. Additionally, a study by Chadwick and Associates  suggests giant reed also lacks the canopy structure to provide shading of bank-edge river habitats, resulting in warmer water than would be found with a native gallery of willows and cottonwoods. In the Santa Ana River system in California, this lack of streambank structure and shading has been implicated in the decline of native stream fishes including the arroyo chub, three-spined stickleback, speckled dace, and the Santa Ana sucker [9,17].
Giant reed has no structural similarity to any dominant riparian plant it replaces and offers little useful cover or nest placement opportunities for birds. Main stems are vertical with no horizontal structure strong enough to support birds . For example, the southwestern willow flycatcher, an endangered species, has not been reported nesting in any vegetation patches dominated by giant reed . Only a few of bird species have been observed using giant reed for nest sites. Dramatic reductions (50% or more) in abundance and diversity of invertebrates were also documented in giant reed thickets in southern California compared with those found in native willow/cottonwood vegetation . Giant reed's most observed use as cover has been by feral pigs .
Stewardship Overview: Although arundo has been widely cultivated for a long time, little information on its biology or ecology has been published. Its rapid growth rate and strong vegetative competitive ability enables it to quickly invade new areas and dominate local vegetation. Very little has been published regarding effective ways of controlling arundo and it is difficult at this point to suggest the best strategy for managing the species.
Ecological Threat in the United States
Giant reed chokes riversides and stream channels, crowds out native plants, interferes with flood control, increases fire potential, and reduces habitat for wildlife, including the Least Bell's vireo, a federally endangered bird. The long, fibrous, interconnecting root mats of giant reed form a framework for debris dams behind bridges, culverts, and other structures that lead to damage. It ignites easily and can create intense fires.
Giant reed can float miles downstream where root and stem fragments may take root and initiate new infestations. Due to its rapid growth rate and vegetative reproduction, it is able to quickly invade new areas and form pure stands at the expense of other species. Once established, giant reed has the ability to outcompete and completely suppress native vegetation.
Arundo donax, Giant Cane, is a tall perennial cane growing in damp soils, either fresh or moderately saline. Other common names include Carrizo, Arundo, Spanish cane, Colorado River Reed, Wild cane, and Giant reed.
Arundo donax is native to eastern and southern Asia, the Mediterranean Basin, and probably also parts of Africa and southern Arabian Peninsula. It has been widely planted and naturalised in the mild temperate, subtropical and tropical regions of both hemispheres (Herrera & Dudley 2003), especially in the Mediterranean, California, the western Pacific and the Caribbean. It forms dense stands on disturbed sites, sand dunes, in wetlands and riparian habitats.
Arundo donax generally grows to 6 metres (20 ft), in ideal conditions it can exceed 10 metres (33 ft), with hollow stems 2 to 3 centimetres (0.79 to 1.18 in) diameter. The leaves are alternate, 30 to 60 centimetres (12 to 24 in) long and 2 to 6 centimetres (0.79 to 2.36 in) wide with a tapered tip, grey-green, and have a hairy tuft at the base. Overall, it resembles an outsize common reed (Phragmites australis) or a bamboo (Subfamily Bambusoideae).
Arundo donax flowers in late summer, bearing upright, feathery plumes 40 to 60 centimetres (16 to 24 in) long, that are usually seedless or with seeds that are rarely fertile. Instead, it mostly reproduces vegetatively, by underground rhizomes. The rhizomes are tough and fibrous and form knotty, spreading mats that penetrate deep into the soil up to 1 metre (3.3 ft) deep (Alden et al., 1998; Mackenzie, 2004). Stem and rhizome pieces less than 5 centimetres (2.0 in) long and containing a single node readily sprouted under a variety of conditions (Boose and Holt, 1999). This vegetative growth appears to be well adapted to floods, which may break up individual A. donax clumps, spreading the pieces, which may sprout and colonise further downstream (Mackenzie 2004).
Arundo donax (L.) is a tall, perennial C3 grass species belongs to the subfamily Arundinoideae of the Poaceae family. The hollow stems, 3 to 5 cm thick, have a cane-like appearance similar to bamboo. Mature stands can reach a height up to 8 m. Stems produced during the first growing season are unbranched and photosynthetic. It is an asexually reproducing species due to seed sterility. It needs to be established by vegetative propagation, due to a lack of viable seed production. Underground it produces an extensive network of large, but short rhizomes like bulbs, and fibrous tap roots. In the Mediterranean, where a temperate climate is characterized by warm and dry summer and mild winter, giant reed new shoots emerge around March, growing rapidly in June – July and producing stems and leaves. From late July the lower leaves start to dry, depending to seasonal temperature patterns. Crop drying accelerates during autumn when anthesis occurs from the beginning of October to the end of November. In this phonological stage moisture contents fall significantly. In winter-time giant reed stops its growth because of low temperatures and regrowth occurs in the following springtime. In Central Europe giant reed behaves as an annual energy crop for the low soil temperatures and poor freeze tolerance lack of the rhizomes. The base growth temperature reported for giant reed is 7°C, and a maximum cut-off is at 30°C. It has a high photosynthetic capacity, associated with absence of light saturation. Carbon dioxide exchange rates is high compared to other C3 and C4 species. Under natural condition, the maximum CO2 uptake ranged between 19.8 and 36.7 µmol m−2 s−1, depending on irradiance, leaf age, and it is regulated by leaf conductance.
In most areas where giant reed grows (Mediterranean area and US), viable seeds are not produced. On the other hand, sterility is an obstacle for breeding programs which aim to increase the productivity and biomass quality for energy conversion. Asexual reproduction drastically reduces genetic variability. It is reported that sterility of giant reed is as a result of a failure of the megaspore mother cell to divide. A total of 185 clones of A. donax were collected from California to South Carolina and genetically fingerprinted with the SRAP and TE based markers. Giant reed exhibited no molecular genetic variation despite the wide genomic coverage of the markers used in this study. The molecular data strongly point to a single genetic clone of A. donax in the United States, although multiple introductions of this plant into the United States have been documented. Another study was conducted in the Mediterranean area on sampling giant reed from 80 different sites, and a low gene diversity was detected. Results indicate the occurrence of post-meiotic alterations in the ovule and pollen developmental pathway. AFLP data support a monophyletic origin of giant reed and suggest that it originated in Asia and began to spread into the Mediterranean Basin.
Giant reed is adapted to a wide variety of ecological conditions, but is generally associated with riparian and wetland systems. It is distributed across the southern United States from Maryland to California. Plants can grow in a variety of soils from heavy clays to loose sands and gravelly soils, but prefer wet drained soils where they produce monotypic dense stands. In soil contaminated with arsenic, cadmium and lead, giant reed was found to grow rapidly, showing a strong metal-tolerance with a limited metal translocation from roots to shoots. In this study it is underlined that accumulation of As, Cd and Pb in shoots of giant reed is low while metal concentration in roots is high, and the anatomical characteristics of stem tissues are thick and homogeneous according to SEM image. In Pakistan, where the detection of arsenic in ground waters has threatened the use of groundwater as major source of drinking water, a research highlighted the phytoremediation potential of A. donax when grown in hydroponics cultures containing arsenic concentrations up to 1000 µg l−1. Giant reed was able to translocate the metals absorbed into the shoot and to accumulate metals in the stalk and leaves above the root concentration without showing any toxic effects up to As concentration of 600 µg l−1. Furthermore, the plant is not consumed by herbivores, a positive trait in phytoremediation plants.
An increased environmental concern is the health of soil system as one of the main factor affecting quality and productivity of agroecosystems. Around the world, several regions are subjected to a decline of fertility due to an increasing degradation of soils, loss of orgnanic matter and increasing desertification. Recently research was carried out to evaluate, in the same pedological and climatic conditions, the impact of three long-term (14 years) agricultural systems, continuous giant reed, natural grassland, and cropping sequence, on the organic-matter characteristics and microbial biomass size in soil. The study pointed out that a long term Giant reed cropping system, characterized by low tillage intensity, positively affect the amount and quality of soil organic matter. Arundo donax showed greater values than tilled management system for total soil organic carbon, light fraction carbon, dissolved organic carbon, and microbial biomass carbon. Regarding the humification parameters, there were noticed any statistically differences between giant reed and a cropping sequence (cereals-legumes cultivated conventionally).
Management in riparian habitats
Arundo is a highly invasive plant in southwestern North American rivers, and its promotion as a bio-fuel in other regions is of great concern to environmental scientists and land managers.Arundo donax was introduced from the Mediterranean to California in the 1820s for roofing material and erosion control in drainage canals in the Los Angeles area (Bell 1997; Mackenzie 2004). Through spread and subsequent plantings as an ornamental plant, and for use as reeds in woodwind instruments, it has become naturalised throughout warm coastal freshwaters of North America, and its range continues to spread. It has been planted widely through South America and Australasia (Boose and Holt 1999; Bell 1997) and in New Zealand it is listed under the National Pest Plant Accord as an "unwanted organism". Despite its invasive characteristics in regions around the world where it is not native, Arundo is being promoted by the energy industry as a bio-fuel crop. Some of the regions, such as the southeastern United States have natural disturbances, such as hurricanes and floods, that could widely disperse this plant.
It is among the fastest growing terrestrial plants in the world (nearly 10 centimetres (3.9 in) / day; Dudley, 2000). To present knowledge Arundo does not provide any food sources or nesting habitats for wildlife. Replacement of native plant communities by Arundo results in low quality habitat and altered ecosystem functioning (Bell 1997; Mackenzie 2004). For example, it damages California's riparian ecosystems by outcompeting native species, such as willows, for water. A. donax stems and leaves contain a variety of harmful chemicals, including silica and various alkaloids, which protect it from most insect herbivores and deter wildlife from feeding on it (Bell 1997; Miles et al. 1993; Mackenzie 2004). Grazing animals such as cattle, sheep, and goats may have some effect on it, but are unlikely to be useful in keeping it under control (Dudley 2000).
Arundo donax appears to be highly adapted to fires. It is highly flammable throughout the year, and during the drier months of the year (July to October), it can increase the probability, intensity, and spread of wildfires through the riparian environment, changing the communities from flood-defined to fire-defined communities. After fires, A. donax rhizomes can resprout quickly, outgrowing native plants, which can result in large stands of A. donax along riparian corridors (Bell 1997; Scott 1994). Fire events thus push the system further toward mono-specific stands of A. donax.
A waterside plant community dominated by A. donax may also have reduced canopy shading of the in-stream habitat, which may result in increased water temperatures. This may lead to decreased oxygen concentrations and lower diversity of aquatic animals (Bell 1997).
As the impact of Arundo donax increased in the environment and native species various efforts have been taken to reduce its population. It has few natural enemies in its introduced range. Several Mediterranean insects have been imported into the United States as biological control agents (Bell, 1997; Miles et al. 1993; Mackenzie 2004, Goolsby 2007), namely Arundo wasp, Tetramesa romana; the Arundo scale, Rhizaspidiotus donacis; and the Arundo fly, Cryptonevra has known to have some effect in damaging the plant. Tetramesa romana and more recently Rhizaspidiotus donacisis were registered in the US as biological control agents.
Other remedies like using mechanical force have also been employed since outside its native range Arundo donax doesn’t reproduce by seeds, so removing its root structure can be effective at controlling it. Also preventing it from getting sunlight will deplete the plant of its resources(Mackenzie 2004). Systemic herbicides and Glyphosate are also used as chemical remedies.
There are no documented invasions by Arundo donax in the Southeastern United States where A. donax has been present in some cases for over 200 years.
Energy crops are plants which are produced with the express purpose of using their biomass energetically  and at the same time reduce carbon dioxide emission. Biofuels derived from lignocellulosic plant material represent an important renewable energy alternative to transportation fossil fuels. Perennial rhizomatous grasses display several positive attributes as energy crops because of their high productivity, low (no) demand for nutrient inputs consequent to the recycling of nutrients by their rhizomes, exceptional soil carbon sequestration - 4X switchgrass, multiple products, adaptation to saline soils and saline water, and resistance to biotic and abiotic stresses.
Giant reed is one of the most promising crops for energy production in the Mediterranean climate of Europe and Africa, where it has shown advantages as an indigenous crop (already adapted to the environment), durable yields, and resistant to long drought periods. Several field studies have highlighted the beneficial effect of giant reed crop on the environment due to its minimal soil tillage, fertilizer and pesticide needs. Furthermore it offers protection against soil erosion, one of the most important land degradation processes in Mediterranean and US environments. A. donax bioenergy feedstock has an impressive potential for several conversion processes. Dried biomass has a direct combustion high heating value of 3,400 kJ/kg (8,000 BTU/lb). In Italy, Arundo donax was used in one instance from 1937 to 1962 on a large-scale industrial basis for paper and dissolving pulp. This interest was stimulated primarily by the desire of the dictatorship, just before World War II, to be independent of foreign sources of textile fibers and the desire for an export product. According to historic record made by Snia Viscosa, giant reed was established on 6 300 ha in Torviscosa (Udine), reaching the average annual production of 35 t ha−1. Today several screening studies on energy crops have been carried out by several Universities in US as well as in EU to evaluate and identify best management practices for maximizing biomass yields and assess environmental impacts.
Establishment is a critical point of cultivation. Stem and rhizome have a great ability to sprout after removal from mother plant and both can be used for clonal propagation. The use of rhizomes were found to be the better propagation method for this species, achieving better survival rate. In this field study, it was noticed how the lowest density (12 500 rhizomes ha−1) resulted in taller and thicker plants compared to denser plantation (25 000 rhizomes ha−1). Seedbed preparation is conducted in the spring, immediately before planting, by a pass with a double-disk harrowing and a pass with a field cultivator. Giant reed has the possibility of adopting low plant density. The rhizomes were planted at 10–20 centimetres (3.9–7.9 in) of soil depth, with a minimum plant density of 10 000 plants per ha), while mature stems, with two or more nodes, can be planted 10–15 centimetres (3.9–5.9 in) deep. In order to ensure good root stand and adequate contact with the soil, sufficient moisture is needed immediately after planting. Pre-plant fertilizer is distributed according to the initial soil fertility, but usually an application of P at a rate of 80–100 kilograms (180–220 lb) ha−1 is applied.
A. donax maintains a high productive aptitude without irrigation under semi-arid climate conditions. In South Italy, a trial was carried out testing the yields performance of 39 genotypes, and an average yields of 22.1 t ha−1 dry matter in the second year were reached, a comparable result with others results obtained in Spain (22.5 t ha−1) as well as in South Greece (19.0 t ha−1). Several reports underlined that it is more economical to grow giant reed under moderate irrigation.
In order to evaluate different management practices, nitrogen fertilizer and input demand was evaluated in a 6-year field study conducted at the University of Pisa. Fertilizer enhanced the productive capacity in the initial years, but as the years go by and as the radical apparatus progressively deepens, the differences due to fertilizer decrease until disappearing. Harvest time and plant density were found to not affect the biomass yields.
Due to its high growth rate and superior resource capture capacity (light, water and nutrients), A. donax is not affected by weed competition from the second year. An application of post-emergence treatment is usually recommended. Giant reed has few known disease or insect pest but in intensive cultivation no pesticides are used.
To remove giant reed at the end of crop cycle, there are mainly two methods: mechanical or chemical. An excavator can be useful to dig out the rhizomes or alternatively a single late-season application of 3% glyphosate onto the foliar mass is efficient and effective with least hazardous to biota. Glyphosate was selected as the most appropriate product after specific considerations on efficacy, environmental safety, soil residual activity, operator safety, application timing, and cost-effectiveness. However, glyphosate is only effective in fall when plants are actively transporting nutrients to the root zone, and multiple retreatments are usually needed. Other herbicides registered for aquatic use can be very effective in controlling Arundo at other times of the year.
Arundo donax is strong candidate for use as a renewable biofuel source because of its fast growth rate, ability to grow in different soil types and climatic conditions. A. donax will produce an average of three kilograms of biomass per square metre (25 tons per acre) once established. The energy density of the biomass produced is 17 MJ/Kg regardless of fertilizer usage.
Studies in the European Union have identified A. donax as the most productive and lowest impact of all energy biomass crops (see FAIR REPORT E.U. 2004).
Arundo donax's ability to grow for 20 to 25 years without replanting is also significant.
In the UK it is considered suitable for planting in and around water areas 
Studies have found this plant to be rich in active tryptamine compounds, but there are more indications of the plants in India having these compounds than in the United States. Toxins such as bufotenidine and gramine have also been found.
The dried rhizome with the stem removed has been found to contain 0.0057% DMT, 0.026% bufotenine, 0.0023% 5-MeO-MMT. The flowers are also known to have DMT and the 5-methoxylated N-demethylated analogue, also 5-MeO-NMT. The quite toxic quaternary methylated salt of DMT, bufotenidine, has been found in the flowers, and the cyclic dehydrobufotenidine has been found in the roots. A. donax is also known to release volatile organic compounds (VOCs), mainly isoprene.
Arundo donax has been cultivated throughout Asia, southern Europe, northern Africa, and the Middle East for thousands of years. Ancient Egyptians wrapped their dead in the leaves. The canes contain silica, perhaps the reason for their durability, and have been used to make fishing rods, and walking sticks. Its stiff stems are also used as support for climbing plants or for vines.
Mature reeds are used in construction as raw material given their excellent properties and tubular shape. Its resemblance to bamboo permits their combination in buildings, though Arundo is more flexible.
In rural regions of Spain, for centuries there has existed a technique named "cañizo", consisting of rectangles of approximately 2 by 1 meters of weaved reeds to which clay or plaster could be added. A properly insulated "cañizo" in a roof could keep its mechanical properties for over 60 years. Its high silicon content allows the cane to keep its qualities through time.
Its low weight, flexibility, good adherence of the "cañizo" fabric and low price of the raw material have been the main reasons that made this technique possible to our days. However, in the last decades the rural migration from countryside to urban centers and the extensive exploitation of land has substituted traditional crops. This has threatened very seriously its continuity.
Recently, initiatives are being taken to recover the use of this material combining ancient techniques from the Marshes of Southern Iraq Mudhif with new materials.
Diverse associations and collectives, such as CanyaViva, are pioneering in the research in combination with Spanish universities.
A. donax is the principal source material of reed makers. The cane is rendered into reeds for clarinets, saxophones, oboes, bassoons, bagpipes, and other woodwind instruments. The "Var country" in southern France contains the best-known supply of instrument reeds.
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Considerable difficulty may be experienced in distinguishing immature plants of Arundo, Neyraudia and Phragmites, and dissecting the spikelets will be of little use. Phragmites can be distinguished by the silky beard at the bases of the lowest panicle branches which is absent from the other two genera. The ligule of Arundo is membranous while that of Phragmites and Neyraudia is a fringe of hairs. The leaves of Arundo are very much broader than in the other genera and are conspicuously cordate or rounded at the base.
The culms have many uses, including light construction, basket making, matting, musical pipes, and ornaments.
[Distinguished by general appearance from two other large grasses with plumelike panicles: Neyraudia reynaudiana (Kunth) Keng., Burma reed or silk reed, and Phragmites australis (Cav.) Steud. The following characters will also separate the three: Phragmites has naked lemmas; Arundo has hairy lemmas and a naked rachilla; Neyraudia has naked lemmas and a hairy rachilla. All three species grow around canals.]
Names and Taxonomy
Comments: Kartesz 1994 recognized two varieties of Arundo donax; Kartesz 1999 no longer distinguishes between varieties.
(Poaceae) [13,40,53,56,57,62,63,69,77,103,105,107]. One variety of giant reed
is recognized in the literature:
Arundo donax L. var. versicolor (P. Mill) Stokes [53,107].
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