Phragmites australis is a tall, perennial grass that can grow to heights of 15 ft. (4.6 m) or more. Broad, pointed leaves arise from thick, vertical stalks.
Leaves are 6-23.6 in. (15-60 cm) long, 0.4-2.4 in. (1-6 cm) wide, flat and glabrous.
The flower heads are dense, fluffy, gray or purple in color and 5.9-15.7 in. (15-40 cm) long. Flowering occurs from July to October.
The seeds are brown, light weight, and about 0.3 in. (8 mm) long. In the fall the plant turns brown, and the inflorescences persist throughout the winter.
Native to Eurasia and Africa.
Disturbed habitats, brackish or salt marshes and flats, fens, fresh tidal marshes or flats, marshes, shores of rivers or lakes, wetland edges.
Reproduction is thought to take place mainly through vegetative means via rhizome and stolon fragments. Rhizomes spread horizontally during the growing season. New stalks shoot in spring, and flowers appear in late June with bushy panicles. Seeds form by August to early fall and are dispersed between November and January. Following seed set, nutrients are translocated down into the rhizomes and the above-ground portions of the plants die back for the season. Water depths of more than 5cm and salinities above 20ppt (2%) prevent germination. Percentage of germination increases with increasing temperature from 16 to 25˚C while the time required to germinate decreases from 25 to 10 days over the same temperature range.
Common reed replaces native grasses, sedges, and herbaceous plants. It provides poor quality habitat for insects, birds and amphibians. Fish populations that reproduce in wetlands and marshes inundated with phragmites suffer higher egg and juvenile mortality. The plant also exudes allelopathic compounds from its roots, causing root death of nearby native plants.
Common reed seed head, 1559068, Ohio State Weed Lab, The Ohio State University, Bugwood.org
Common reed seed head, 1237064, Joseph McCauley, US Fish and Wildlife Service, Bugwood.org
Common reed infestation, 1559071, Ohio State Weed Lab, The Ohio State University, Bugwood.org
Common reed root, 5487096, Leslie J. Mehrhoff, University of Connecticut, Bugwood.org