Joseph McCauley, USFWS

Common Reed

Phragmites australis (Cav.) Trin. ex Steud.
Grass family (Poaceae)

Origin: Europe

Background
European forms of Phragmites were probably introduced to North America by accident in ballast material in the late 1700s or early 1800s. Recent research using genetic markers has demonstrated that three separate lineages occur in North America – one endemic and widespread (native), one whose nativity is not certain that occurs across the southern U.S. from California to Florida and into Mexico and Central America (‘Gulf Coast’ type) and one from Europe (introduced invasive), which is the focus of this writing. The European Phragmites first established along the Atlantic coast and then spread across the continent over the course of the 20th century. The native form was historically more widespread, occurring throughout Canada and most of the U.S. except for the Southeast (Texas to Florida and north to North Carolina). It remains fairly widespread in the western U.S.

Native Americans used common reed for arrow shafts, musical instruments, ceremonial objects, cigarettes, and leaves and stems for constructing mats. Preserved remains of native Phragmites 40,000 years old have been found in the Southwestern United States indicating that it is a part of the native flora of that region. In coastal areas, preserved rhizome fragments dating back 3,000-4,000 years before present have also been found in salt marsh sediments indicating that it is also native to these habitats. Both native and introduced forms have been used for duckblinds.

Distribution and Habitat
Common reed occurs in disturbed to pristine wet areas including tidal and non-tidal wetlands, brackish and fresh-water marshes, river edges, shores of lakes and ponds, roadsides and ditches. It prefers full sun and can tolerate fresh to mesohaline salinities.

Ecological Threat
Common reed is a vigorous growing plant that forms dense monotypic stands that consume available growing space and push out other plants including the native subspecies. It also alters wetland hydrology, increases the potential for fire and reduces and degrades wetland wildlife habitat due in part to its very dense growth habit. There is currently no evidence for of hybridization between native and introduced forms occurring in the field.

Description and Biology

• Plant: perennial grass, stems to 15 ft., somewhat rough to the touch, lack fungal spots but some mildew may be present.
• Leaves: blue green and darker than the native form; elongate, typically 1-1½ in. wide at their widest point; leaf sheaths adhere tightly to stem and persist through the winter; ligule is less than 1 mm long.
• Flowers, fruits and seeds: flowers in bushy panicles, usually purple or golden in color; upper glumes 4.5-7.5 mm, lower glumes 2.5-5.0 mm (most <4.0).
• Spreads: by seed which is dispersed by wind and water; vegetatively through rhizomes and transport of rhizome fragments.
• Look-alikes: native form of Phragmites; other large grasses with plume-like inflorescences.

Prevention and Control
Avoid spread of plants and plant parts to uninfested plant areas (see Control Options).

Bill Johnson