Giant Reed (Arundo donax)
Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.
Giant reed grass, cornlike stems, thicket forming in distinct clumps to 20 feet (6 m) in height, with gray-green and hairless stems, long-lanceolate alternate leaves jutting from stems and drooping at the ends, and large plumelike terminal panicles. Seed infertile. Spreading from short tuberous rhizomes that form knotty, spreading mats that penetrate deep into the soil. Dried grass remains standing in winter and spring while low and sheltered plants may remain green.
Somewhat succulent and fibrous, with round cross section to 1 inch (2.5 cm). Solid jointed every 1 to 8 inches (2.5 to 20 cm) and covered by overlapping leaf sheaths. Gray to yellowish green. Initially white pithed and becoming hollow between joints. Old stems sometimes persistent into the following summer.
Alternate, cornlike, long lanceolate with both surfaces hairless, clasping stem with conspicuous whitish base. Eighteen to 30 inches (45 to 76 cm) long and 1 to 4 inches (2.5 to 10 cm) wide near base. Margins and ligule membranous (about 1 mm). Midvein whitish near base becoming inconspicuous towards tip. Veins parallel. Sheaths overlapping, hairless, and semiglossy. White and green variegated forms also escape from cultivation.
August to September. Terminal erect dense plumes of whorled, stemmed flowers to 36 inches (1 m) long. Husks hairy, membranous with several veins, and greenish to whitish to purplish.
October to March. Dense terminal plume, spindle shaped, densely hairy. Grain infertile.
Occurs mainly on upland sites as scattered dense clumps along roadsides and forest margins, migrating from old home plantings by displaced rhizome fragments. Persistent infestations by dense branching tuberous rhizome growth. Probable spread by movement of stem and rhizome parts in soil or by road shoulder grading and by running water. Plants believed to be sterile and not producing viable seeds.
Resembles golden bamboo (Phyllostachys aurea Carr. ex A. & C. Rivière), another large grasslike plant that is woody in character. Closely resembles common reed [Phragmites australis (Cav.) Trin. ex Steud.], which has similar large hairy seed heads, but fanned in a loose plume and not erect, and which occurs mainly near swamps, marshes and other wet habitats.
History and use
Introduced from Western Asia, Northern Africa, and Southern Europe in the early 1800s. Ornamental and reeds for musical instruments (woodwinds).
Found throughout the region with scattered dense infestations in every State. Especially frequent along highway and roadside margins.
- Oppose widespread planting of this species for fiber or fuels.
- Do not plant. Remove prior plantings, and control sprouts. Bag and dispose of plants in a dumpster or burn.
- Frequent repeated cutting to groundline may result in control.
- Burning treatments are suspected of having minimal effect due to underground rhizomes.
Recommended control procedures
- Thoroughly wet all leaves with one of the following herbicides in water with a surfactant (September or October with multiple applications to regrowth): when safety to surrounding plants is desired, a glyphosate herbicide as a 4-percent solution (1 pint per 3-gallon mix) directed at this plant and away from surrounding plants; Arsenal AC* as a 1-percent solution (4 ounces per 3-gallon mix); or a combination of the two herbicides; Arsenal AC* as a 0.5-percent solution (2 ounces per 3-gallon mix) and a glyphosate herbicide as a 4-percent solution (1 pint per 3-gallon mix).
* Nontarget plants may be killed or injured by root uptake.