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Scientific Name:

Common Name:

Arundo donax L.
Giant reed
Family: Poaceae

USDA Plant Code: ARDO4

Habitat: Wetlands

Growth Habit: Perennial Subshrub, Shrub, Graminoid

Native Environment: W. Asia, N. Africa, S. Europe

Introduction


Problems Caused
Giant reed is thought to have been introduced into California during the early 1800s. It presently is planted throughout the southern half of the US as an ornamental, and is used in the arid Southwest for erosion control along ditches. Giant reed also is used in the manufacture of reeds for musical instruments, in basket making, for fishing rods, and as livestock fodder. Giant reed is known to infest riparian areas and stream channels, displace native plants, interfere with flood control, and negatively impact wildlife habitat.

Regulations
Giant reed is listed as a significant threat in SC, and is included in the invasive species lists of GA, VA, and TN (the only mid-southern state recognizing it as a potential threat).

Description



Giant Reed Can Reach 20 ft or More in Height
Vegetative Growth
Giant reed resembles the Asian bamboos, Phyllostachys species, and common reed (Phragmites australis (Cav.) Trin. ex Steud.), which also produces large hairy seed heads when in fruit. However, common reed occurs primarily in and along swamps, marshes, and other wetland habitats (versus the more upland and inland habitats characteristic of giant reed).

Giant reed stems also resemble maize (corn) to some degree. However, a key distinguishing feature of the plant is that it tends to form distinct clumps with stems reaching to 20 ft (6m) tall. These clumps, over time, can grow to a very large diameter (60 ft or more). It usually produces grayish-green, glabrous (hairless) stems, with long lance-shaped leaf blades (18-30 inches long by 1-4 inches wide near base). The leaves are arranged alternately along the stems and droop at the ends (as in maize). The dead and dried aboveground parts typically remain standing throughout winter and spring.

Giant reed stems are round in cross section to 1 inches or more in diameter, with solid nodes at 1-8 inches intervals, separated by hollow internode segments. The grayish to light green stems are covered by overlapping, glabrous leaf sheaths.

Flowering
Giant reed flowers during later summer: August to September. It produces erect, terminal dense plumes of whorled stemmed flowers, with the clusters to 39 inches long. The flowers are hairy and greenish to whitish to purplish. The dense terminal “fruiting” plumes may be present from October to March, but fertile seeds are unknown from this species in the US.


The Massive Underground Rhizome of the Giant Reed Stores Large Quantities of Starch, Causing it to be Difficult to Control
Dispersal
Because it is not known to be fertile in the US, reproduction of giant reed is primarily through rhizomes (belowground stems) which root and sprout readily. Giant reed fragments can float miles downstream and then successfully take root and initiate new infestations. Rapid growth following vegetative dispersal permits this species to quickly invade new areas and form pure stands at the expense of native species.

Spread By
Giant reed may spread by movement of stem parts in cut or fill soil, or by road shoulder grading. Giant reed has been sold for ornamental purposes.

Habitat


Giant reed occurs largely in disturbed upland habitats, as scattered dense clumps along roadsides and forest margins, often thought to migrate from old home plantings by displaced rhizome fragments. Giant reed can become established in moist places such as ditches, streams, and riverbanks, but it tends to grow best in well drained soils where abundant moisture is available. It is broadly tolerant of soil conditions, including high salinity, and can grow well in soil from heavy clays to loose sands.

Distribution


United States
Giant reed is distributed in the southern half of the continental US, from the Atlantic to Pacific coasts. It is a widespread invasive in California.

MidSouth
This species is present in all five MidSouth states, but it has been very poorly recorded. The USDA PLANTS database indicates its presence in very few counties of AL, AR, MS, and TN, but the IPAMS workgroup has recorded giant reed in numerous counties not represented in the PLANTS distribution maps. There is a clear need for more mapping throughout the MidSouth.

IPAMS Surveys:

Control Methods


Biological
While several insects are under investigation by USDA-ARS as potential biological control agents for giant reed, no agents are currently operational. Grazing by goats has been used as a control technique in western locations, where either burning or herbicide use might raise concerns.

Chemical Control Options for Giant Reed
Herbicide Spot Rate Broadcast Rate Nonionic Surfactant Notes
Glyphosate 3-5% solution 2 lbs ae/acre
(7.5 pints/acre)
0.25-0.5% v/v Systemic with slow results
Imazapyr 3-5% solution 1.5 lbs ai/acre
(6 pints/acre)
0.25% v/v Systemic with slow results
Chemical
Systemic herbicides, such as glyphosate, may be applied to clumps of giant reed, after flowering. Glyphosate and imazapyr have been used to successfully manage giant reed, but repeated treatments may be necessary for complete control. Glyphosate application made late in the season are more efficacious than those made early in the growing season. The Habitat (imazapyr) label recommends spring treatments while plants are actively growing, but no published accounts substantiate the rate or timing of application.

Mechanical
Repeated mowing may be effective but in some cases re-growth from root fragments can occur. Hand digging and removal is theoretically possible as a control technique, but the extensive and massive rhizomes make this technique unrealistic.

Physical
Prescribed burning either alone or in combination with herbicide treatments is feasible to reduce biomass and control

References


Goolsby, J.A. and P. Moran. 2009. Host range of Tetramesa romana Walker (Hymenoptera:Eurytomidae), a potential biological control of giant reed, Arundo donax L. in North America. Biological Control 49:160-168.

Hoshovsky, M. 1986. Element Stewardship Abstract for Arundo donax (Giant Reed). The Nature Conservancy, Arlington, VA. September, 1986. 8pp.

Lawson, D.M., J.A. Geissow, and J.H. Giessow. 2005. The Santa Margarita River Arundo donax Control Project: Development of Methods and Plant Community Response. USDA Forest Service General Technical Report PSW-GTR-195, pp. 229-244.

Miller, J. H. 2003. Nonnative invasive plants of southern forests: a field guide for identification and control. Gen. Tech. Rep. SRS–62. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 93 p. Online resource at http://www.invasive.org/eastern/srs/index.html accessed [25 June 2007].

Miller, J. H., E. B. Chambliss, C. T. Bargeron. 2004. Invasive Plants of the Thirteen Southern States. Invasive.org: Invasive and Exotic Species of North America. Online resource at http://www.invasive.org/ accessed [25 June 2007].

Remaley, T. and C. Bargeron. 2003. Southeast Exotic Pest Plant Council Invasive Plant Manual. Southeast Exotic Pest Plant Council. Online resource at http://www.invasive.org/eastern/eppc/introduction.html accessed [25 June 2007].

Spencer, D.F., W. Tan, P.S. Liow, G.G. Ksander, L.C. Whitehand, S. Weaver, J. Olson, and M. Newhouser. 2008. Evaluation of glyphosate for managing giant reed (Arundo donax L.) Invasive Plant Science and Management 1:248-254.

Spencer, D.F., W. Tan, P.S. Liow, G.G. Ksander, and L.C. Whitehand. 2009. Evaluation of a late summer imazapyr treatment for managing giant reed (Arundo donax). Journal of Aquatic Plant Management 47:40-43.

Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service, 82 pp. Online resource at http://www.invasive.org/eastern/midatlantic/ accessed [25 June 2007].

More Information


Alien Plant Database
http://www.bugwood.org

Geosystems Research Institute, Mississippi State University
http://www.gri.msstate.edu/

Southeast Exotic Plant Pest Council
http://www.se-eppc.org

Southern Weed Science Society
http://www.weedscience.msstate.edu/swss

PLANTS Database, U. S. Department of Agriculture Natural Resources Conservation Service
http://plants.usda.gov/


Contributing Authors


Dr. John D. Madsen, Geosystems Research Institute, Mississippi State University


Contact Info


Dr. Gary N. Ervin
Mississippi State University
Department of Biological Sciences
Box 9627
Mississippi State, MS 39762-9627
Ph. (662)325-1203
gervin@biology.msstate.edu

Geosystems Research Institute
Contact: John D. Madsen, Ph.D.  •  WebMaster