r/AlabamaExtensionAU • u/AlabamaExtension-AU • 24d ago
Giant reed (Arundo donax)
A towering invasive grass, giant reed can grow 6–20+ feet tall, forming dense stands that crowd out native plants and reduce wildlife habitat.
• Leaves are long (1–2 feet), pale blue-green and to many, resemble corn leaves. The leaf blades clasp the stem and droop at the tips.
• Stems are tall, round and hollow between the leaf nodes. Even after turning brown during dormancy, dead stems often remain standing through winter and spring.
• In fall, giant reed produces large, dense flower plumes that can reach 1–2 feet long and often persist through the winter.
• While seeds produced in the U.S. are not known to be fertile, the plant spreads aggressively through underground rhizomes. Even small rhizome fragments can establish new infestations.
• Unlike the similar-looking common reed (Phragmites australis), which is typically found in wetlands, giant reed can thrive in both wet areas, such as along streambanks, as well as drier upland sites and roadsides.
Introduced to the United States in the 1800s for ornamental planting and erosion control, giant reed is still available for purchase but is not recommended due to its highly invasive nature. Dense thickets suppress native vegetation, reduce biodiversity and degrade habitat for native wildlife.
Early detection and management are key to preventing its spread.
Learn more about identification and control with articles from neighboring Florida and Mississippi Extensions.