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.

Culms up to 6 m, usually simple. Leaves: lamina up to 60 × 6 cm, glaucous. Panicle 30–60 cm, oblong. Spikelets 12–18 mm, usually with 3 florets; lanceolate; lemmas lanceolate.

More info for the terms: cover, hydrophyte

Though accounts in the literature vary, a review by Bell [11] 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 [49])[28], 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 [74] and along ditches, streams, and seeps in arid and cis montane regions of California (Robbins and others 1951, as cited in [49]).

According to Bell [11], giant reed is invasive throughout the warmer coastal freshwaters of the United States from Maryland westward to northern California. Wunderlin [107] recognizes the variety versicolor as occurring in Florida, and Jones and others [53] 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 [71] 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.

(key to state/province abbreviations)
UNITED STATES

AL	AZ	AR	CA	FL	GA
HI	IL	KS	KY	LA	MD
MS	MO	NV	NM	NC	OK
SC	TN	TX	UT	VA	WV
PR	VI

MEXICO

Chih.

Coah.

Son.

Tamps.

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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 [12]:

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

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.

India

Nile region, oases, Mediterranean region, Egyptian desert and Sinai.

Mediterranean region, Sinai, eastwards to Myanmar, introduced elsewhere.

Arundo scriptoria L.:
Egypt (Africa & Madagascar)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Arundo donax var. lanceolata Döll:
Brazil (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Arundo donax var. coleotricha Hack.:
Taiwan (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Arundo donax var. angustifolia Döll:
Brazil (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Arundo donax L.:
Argentina (South America)
Bolivia (South America)
Brazil (South America)
Chile (South America)
Costa Rica (Mesoamerica)
Germany (Europe)
Ecuador (South America)
El Salvador (Mesoamerica)
Ethiopia (Africa & Madagascar)
France (Europe)
Guatemala (Mesoamerica)
Cambodia (Asia)
Iran (Asia)
Italy (Europe)
Bhutan (Asia)
Mexico (Mesoamerica)
Nicaragua (Mesoamerica)
Nepal (Asia)
New Zealand (Oceania)
Corsica (Europe)
Caribbean (Caribbean)
United States (North America)
South Africa (Africa & Madagascar)
Peru (South America)
Suriname (South America)
Spain (Europe)
Uruguay (South America)
Turkmenistan (Asia)
Taiwan (Asia)
Angola (Africa & Madagascar)
Algeria (Africa & Madagascar)
Portugal (Europe)
Burma (Asia)
India (Asia)
Venezuela (South America)
Australia (Oceania)
Japan (Asia)
Kazakhstan (Asia)
Laos (Asia)
Afghanistan (Asia)
China (Asia)
Uzbekistan (Asia)
Colombia (South America)
Pakistan (Asia)
Thailand (Asia)
Tajikistan (Asia)
Vietnam (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Asia

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

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.

Distribution: Pakistan (Baluchistan, Punjab, N.W.F.P. & Kashmir); Mediterranean region eastwards to Burma; North Africa; introduced into many parts of the World.

Mediterranean region, tropical Asia. Introduced into New World.

More info for the term: graminoid

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 [24].

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 [74]. Giant reed has large plume-like panicles. Spikelets are several-flowered with upper florets successively smaller [33].

Giant reed has thick, knotty rhizomes [103] and deeply penetrating roots [74]. 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 [11]).

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.

Perennials, Aquatic, leaves e mergent, Terrestrial, not aquatic, Rhizomes present, Rhizome short and compact, stems close, Rhizome elongate, creeping, stems distant, Stems woody, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem internodes hollow, Stems with inflorescence 2-6 m tall, Stems with inflorescence 6 m or taller, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades disarticulating from sheath, deciduous at ligule, Leaf blades linear, Leaf blades lanceolate, Leaf blade auriculate, Leaf blades 2 or more cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 3-7 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Spikelets conspicuously hairy , Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glumes keeled or winged, Glumes 3 nerved, Glumes 4-7 nerved, Lemma similar in texture to glumes, Lemma 3 nerv ed, Lemma 5-7 nerved, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma awnless, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs equal to lemma, Callus hairs longer than lemma, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Palea keels winged, scabrous, or ciliate, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Perennial, with creeping woody rhizomes. Culms erect, up to 5 m high. Leaf-blades conspicuously distichous, linear-lanceolate, rounded or cordate at the base, 30-60 cm long, 2.5-5 cm wide, glabrous, smooth, long-attenuate at the tip. Panicle 30.60 cm long and 5.8(10) cm wide. Spikelets 10-15 mm long; glumes subequal, lanceolate to narrowly lanceolate, (8-)10-13 mm long, the lower a little shorter than the upper; lemmas lanceolate, (6)8.5-13 mm long, 3-5-nerved, 3 of the nerves produced as short aristae, hairy all over the back below the middle with hairs up to 7 mm long.

Robust reed from a thick knotty rhizome. Culms very stout, erect, 2–6 m tall, 1–1.5 cm in diam., unbranched or with bamboolike clusters of slender branches from nodes. Leaf sheaths longer than internodes, usually glabrous except long pilose at mouth; leaf blades 30–60 × 2–5 cm, margins scabrous, tapering to a slender filiform apex; ligule 0.7–1.5 mm. Panicle 30–60 cm, dense, usually purplish; branches 10–25 cm, ascending. Spikelets 10–15 mm, florets 2–5; glumes narrowly lanceolate, 8–12 mm, 3–5-veined, lower glume acute, upper glume sharply acuminate; lemmas linear-lanceolate, 8–11 mm, 3–7-veined, dorsal hairs 5–6 mm, apex minutely bidentate with 1–2 mm awnlet from sinus, lateral veins also shortly extended; palea 1/2 length of lemma body. Fl. and fr. Oct–Dec.

Tall coarse perennial tufted with short thick rhizome. Culm about 1-3 cm in diameter. Blades 2-4 cm wide, the margins scabrid; ligule 2 mm long, fimbriate on upper margin, siliceous on dorsal side; sheath usually longer than the internode, glabrous or subdensely pubescent (var. coleotricha Hackel). Panicle ample, 30-70 cm long, axiss strigose at nodes. Spikelets 3-4-flowered or more, terete, 10-15 mm long; glumes chartaceous, lanceolate, siliceous apex with short awn or acute; the lower glume about 12 mm long, 3-5-nerved, rarely 4-nerved, covered with a few silky hairs on the backside; the uppe glume about 10 mm long, 3-5-nerved; lemma 10-12 mm long, 5-nerved middle nerve prolonged into a 3 mm long awn, 2 lateral awn slightly cuspidate, basal part densely covered with long silky hairs which are nearly as long as the lemma; palea about 5 mm long, 2-keeled, the margins ciliate, apex truncate; lodicules 2, truncate, nerved, stamens 3. anther 2.5 mm long.

2100-2440 m

Aira bengalensis (Retzius) J. F. Gmelin; Amphidonax bengalensis (Retzius) Nees ex Steudel (1854), not Roxburgh ex Nees (1836); Arundo bengalensis Retzius; A. coleotricha (Hackel) Honda; A. donax var. coleotricha Hackel; Donax arundinaceus P. Beauvois; D. bengalensis (Retzius) P. Beauvois; Scolochloa donax (Linnaeus) Gaudin.

Type fragment for Arundo donax var. coleotricha Hack.
Catalog Number: US 78855
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): T. Makino
Locality: Tamsui., Taiwan Island, Taiwan, Asia-Temperate

More info for the terms: frequency, hydrophyte

 
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 [79]. 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 [74]. In California, it typically grows along lakes, streams, drains and other wet sites [11]. 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 [28]. 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 [87]. 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 [28]. 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 [80].

Giant reed tolerates excessive salinity and periods of excessive moisture [74]. In South Carolina, it has invaded abandoned rice fields and grows in brackish water [86]. In a greenhouse experiment designed to test the tolerance of giant reed to salt stress, Peck [73] 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 [87] suggest that it requires "well-developed" soils to become established, while DiTomaso [24] 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 [74] 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) [24]. According to Purdue [74], 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.

In California, giant reed is apparently restricted to elevations below 1,640 feet (500 m) [47]. However, Perdue [74] reports it grows at altitudes to 8,000 feet (2,438 m) in the Himalayas.

Elevation ranges reported for giant reed in other areas include:

Nevada:    2,500 to 4,000 feet (760-1,220 m) [56]
New Mexico:    4,000 to 4,500 feet (1,220-1,370 m) [62]
Utah:    2,790 to 4,100 feet (850-1,250 m) [103]

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, hardwood, marsh, shrub, vine

SRM (RANGELAND) COVER TYPES [85]:

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

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

419 Bittercherry

420 Snowbrush

421 Chokecherry-serviceberry-rose

422 Riparian

501 Saltbush-greasewood

502 Grama-galleta

503 Arizona chaparral

504 Juniper-pinyon pine woodland

505 Grama-tobosa shrub

506 Creosotebush-bursage

507 Palo verde-cactus

508 Creosotebush-tarbush

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

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

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

822 Slough

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 [32]:

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

57 Yellow-poplar

58 Yellow-poplar-eastern hemlock

59 Yellow-poplar-white oak-northern red oak

60 Beech-sugar maple

61 River birch-sycamore

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

105 Tropical hardwoods

106 Mangrove

110 Black oak

111 South Florida slash pine

221 Red alder

222 Black cottonwood-willow

232 Redwood

235 Cottonwood-willow

239 Pinyon-juniper

240 Arizona cypress

241 Western live oak

242 Mesquite

243 Sierra Nevada mixed conifer

246 California black oak

249 Canyon live oak

250 Blue oak-foothills pine

255 California coast live oak

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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 [60] 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

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

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

K071 Shinnery

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

K092 Everglades

K098 Northern floodplain forest

K100 Oak-hickory forest

K105 Mangrove

K111 Oak-hickory-pine

K112 Southern mixed forest

K113 Southern floodplain forest

K114 Pocosin

K115 Sand pine scrub

K116 Subtropical pine forest

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 [38]:

FRES12 Longleaf-slash pine

FRES13 Loblolly-shortleaf pine

FRES14 Oak-pine

FRES15 Oak-hickory

FRES16 Oak-gum-cypress

FRES17 Elm-ash-cottonwood

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

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.

River banks and other damp places, but it will also grow when planted in dryish habitats. Fujian, Guangdong, Guizhou, Hainan, Hunan, Jiangsu, Sichuan, Xizang, Yunnan, Zhejiang [Afghanistan, Bhutan, Cambodia, India, Indonesia, Japan, Kazakhstan, Laos, Malaysia, Myanmar, Nepal, Pakistan, Tajikistan, Thailand, Turkmenistan, Uzbekistan, Vietnam; N Africa, C and SW Asia, S Europe; widely introduced elsewhere].

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). 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. 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 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).

Local

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. 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 (Joyce, personal observation in [95]). 

Anecdotal evidence cited in reviews (e.g., [11,28,95]) indicates that giant reed is top-killed by fire, and in most circumstances underground rhizomes survive fire.

More info for the terms: fire regime, fire severity, frequency, fuel, fuel moisture, grass/fire cycle, presence, severity, shrub, wildfire

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 [80] 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 [30] 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 [30]. Recovery of riparian vegetation depends on fire severity and postfire hydrology [22].

Dwire and Kauffman [30] 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 [11] 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 [11]. 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 [30]. 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 [11].

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 [74] in dense stands described as having "large quantities of dry material" [95], 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 [74]. Scott [84] 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 [95]), the Santa Ana River drainage (J. Wright, personal communication in [87]), and the Russian River further north [29]. 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 [95]). Dudley [29] 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 [28]). 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 [95]). In this sense, Bell [11] 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 [11].

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 [101]
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 [72]
basin big sagebrush	Artemisia tridentata var. tridentata	12-43 [81]
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 [70]
desert grasslands	Bouteloua eriopoda and/or Pleuraphis mutica	5-100  [72]
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]
cheatgrass	Bromus tectorum	75,104]
California montane chaparral	Ceanothus and/or Arctostaphylos spp.	50-100 [72]
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  [101]
blackbrush	Coleogyne ramosissima	< 35 to < 100
Arizona cypress	Cupressus arizonica	< 35 to 200
northern cordgrass prairie	Distichlis spicata-Spartina spp.	1-3 [72]
beech-sugar maple	Fagus spp.-Acer saccharum	> 1,000 [101]
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]
yellow-poplar	Liriodendron tulipifera	101]
Everglades	Mariscus jamaicensis	< 10
melaleuca	Melaleuca quinquenervia	70]
wheatgrass plains grasslands	Pascopyrum smithii	72,76,106]
southeastern spruce-fir	Picea-Abies spp.	35 to > 200 [101]
Engelmann spruce-subalpine fir	Picea engelmannii-Abies lasiocarpa	35 to > 200
pine-cypress forest	Pinus-Cupressus spp.	4]
pinyon-juniper	Pinus-Juniperus spp.	72]
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 [101]
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 [101]
pitch pine	Pinus rigida	6-25 [15,44]
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
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	Prosopis glandulosa	64,72]
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-hickory	Quercus-Carya spp.	101]
oak-juniper woodland (Southwest)	Quercus-Juniperus spp.	72]
oak-gum-cypress	Quercus-Nyssa-spp.-Taxodium distichum	35 to > 200 [70]
southeastern oak-pine	Quercus-Pinus spp.	101]
coast live oak	Quercus agrifolia	2-75 [42]
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 [72]
bur oak	Quercus macrocarpa	101]
oak savanna	Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium	2-14 [72,101]
shinnery	Quercus mohriana
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 [72]
baldcypress	Taxodium distichum var. distichum	100 to > 300
pondcypress	Taxodium distichum var. nutans	70]
eastern hemlock-yellow birch	Tsuga canadensis-Betula alleghaniensis	> 200 [101]
western hemlock-Sitka spruce	Tsuga heterophylla-Picea sitchensis	> 200 [4]
elm-ash-cottonwood	Ulmus-Fraxinus-Populus spp.	27,101]

*fire return interval varies widely; trends in variation are noted in the species review
**mean

More info on this topic.

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 [11] and Dudley [28], 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 [28]. However, establishment of giant reed in dense, mature riparian vegetation may be limited [80].

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).

More info for the terms: natural, rhizome

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.

Giant reed reproduces vegetatively by sprouting from rhizomes and stem nodes (reviews by [11,28,49]).

Breeding system: No information is available on this topic.

Pollination: No information is available on this topic.

Seed production: Although giant reed is well adapted in many parts of North America, it rarely, if ever, produces viable seed here (reviews by [11,74])[47].

Seed dispersal: The hairy, light-weight disseminules (individual florets with the enclosed grain) are dispersed by wind [33].

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 [28]. 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 [80] 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 [74]).

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 [28]). 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 [28]).

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 [48] 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 [91]. In a greenhouse experiment, Motamed [68] determined that giant reed stem fragments rooted throughout the growing season.

More info on this topic.

More info for the term: hydrophyte

RAUNKIAER [78] LIFE FORM:
Hydrophyte

More info for the term: graminoid

Graminoid

More info on this topic.

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 [11] 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
State	Time of flowering
California (southern)	late summer [11]
Carolina, North and South	September-October [77]
Florida	all year [107]
New Mexico	June to September [62]

Fl. & Fr. Per.: June - December.

Perennial.

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.

Very little information is available in the literature regarding the biology of 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).

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


No available public DNA sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 6
Specimens with Barcodes: 17
Species With Barcodes: 1

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Global Short Term Trend: Increase of 10 to >25%

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.

More info for the terms: association, cover, fire management, fresh, grass/fire cycle, natural, presence, rhizome

Impacts: Bell [11] 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 [54].

Once established, giant reed often forms monocultural stands that physically inhibit growth of other plant species [11,80]. For example, Douthit [26] 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 [9]. 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) [95].

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 [25]. 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 [99].

Iverson [50] 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 [50].

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 [11].

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 [99].

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 [99].

Prevention: Grading and construction can spread giant reed [80]. 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 [11].

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 [34].

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 [8]. 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 [49]. 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 [28]). 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 [49]. 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 [28]).

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 [28]).

Fire: See Fire Management Considerations.

Biological: Tracy and DeLoach [93] 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 [11]. It is uncertain what natural controlling mechanisms for giant reed are in its countries of origin, although corn borers (Eizaguirre and others 1990 in [11]), spider mites [31], and aphids [65] 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 [94]. A leafhopper in Pakistan utilizes giant reed as an alternate host but attacks corn and wheat [1].

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 [11].

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 [108]. In many areas of California the use of Angora and Spanish goats is showing promise for controlling giant reed [21].

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 [11]. 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 [11]). Bell [11], Hoshovsky [49], and Jackson [52] 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 [11] 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 [97].

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 [11].

These species are introduced in Switzerland.

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 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 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 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 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?

More info for the term: rhizome

Giant reed has been planted extensively for erosion control along drainage canals [49]. Wynd and others [108] report it can also be used to stabilize sand dunes. It is also used for thatching roofs of sheds, barns and other buildings [49]. 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 [2]. Giant reed makes a good quality paper, and in Italy it is used in the manufacture of rayon [24].

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 [74].

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 [74].

More info for the term: cover

Available evidence indicates giant reed provides neither food nor habitat for native species of wildlife [11]. Bell [11] 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 [18], cardiac glycosides, curare-mimicking indoles [39], hydroxamic acid, and numerous other alkaloids (Bell [11] and references therein).

Giant reed is not very palatable to cattle, but they will eat it during dry seasons [49,108]. Domestic goats will also eat it [21,49].

Giant reed is low in protein but has a comparatively high concentration of phosphorus in the upper portions even when grown on soils with an extremely low concentration of this mineral [74,108].

Nutritional content of giant reed. Results are an average of 2 samples for each category and are presented as percentages of oven-dry weight [108]:
	Old plant		Young plant
	Lower half	Upper half	Lower half	Upper half
Total nitrogen	0.63	1.10	0.50	1.96
Protein (total N x 6.25)	3.94	6.88	3.13	12.25
Phosphorus	0.082	0.114	0.105	0.152
Calcium	0.52	0.67	0.30	0.43
Magnesium	0.25	0.32	0.12	0.19
Potassium	2.04	2.42	3.09	3.19
Carbohydrate	23.2	21.7	20.0	20.7

Cover value: Areas dominated by giant reed are largely depauperate of wildlife [9,11,54]. Additionally, a study by Chadwick and Associates [17] 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 [110]. For example, the southwestern willow flycatcher, an endangered species, has not been reported nesting in any vegetation patches dominated by giant reed [97]. 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 [29]. Giant reed's most observed use as cover has been by feral pigs [110].

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.

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.

Arundo donax is a plant of wet habitats but Bor (Grasses Burma Ceyl. Ind. Pak. 415) stated that it will grow in dryish places when once established. Cattle will browse its young leaves but it is not of much account as a fodder grass. In Europe it is extensively cut to make mats, trays and baskets and the Romans used the stems for pens. It is sometimes used for making paper but is commercially of less value than Phragmites australis.

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.

Forms with variegated leaf blades are sometimes cultivated in gar-dens, e.g., var. versicolor (Miller) Stokes (Arundo versicolor Miller), with longitudinally green- and white-striped leaf blades. Arundo donax var. coleotricha refers to a wild variant with pubescent leaf sheaths.

The culms have many uses, including light construction, basket making, matting, musical pipes, and ornaments.

A form with striped leaves (var. versiocolor Stokes) cultivated in Taiwan and Japan.
 [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.]

Comments: Kartesz 1994 recognized two varieties of Arundo donax; Kartesz 1999 no longer distinguishes between varieties.