Common Reed (Phragmites australis) is a perennial, wetland grass, usually 6-15 feet tall, with subspecies both native and non-native to North America. Non-native species that originated from Europe, Asia, and Australia, were most likely introduced to North America by accident in ballast materials during the 1800s. Since the introduction of non-native Phragmites during the 1950s, it has spread all over North America, replacing native species and disturbing natural environments.
Phragmites is usually found in pristine or disturbed areas with slow or stagnant water, such as wetlands, shores of ponds and lakes, marshes, riverbanks, roadsides, and ditches. Phragmites is tolerant to frequent, prolonged flooding, seasonal drying, moderate salinity, and full to partial sun, making the Coastal region of North Carolina an ideal geological range.
Non-native Phragmites often grow in dense clonal strands consisting of both living and standing dead stems. Stems are stout, hollow, erect, unbranched, and usually green with yellow nodes during the growing season. Leaves are blue-green to yellow-green, flat, deciduous, and can grow up to 20 inches long and 1 to 1.5 inches wide. During late July and August, Phragmites is in bloom with flowers that are purple, dense, and plumose.
Non-native Phragmites rapidly form dense stands of stems which outcompete native vegetation for resources. Phragmites turn rich, diverse habitats into monocultures devoid of the diversity needed to support a thriving ecosystem. Non-native Phragmites can alternative habitats in multiple ways, such as change marsh hydrology, decrease salinity, change local topography, and increase fire potential.
Common reed reproduces sexually from seed and vegetatively from stolon’s and rhizomes. The mode of long-distance dispersal of Phragmites occurs through seeds, which is dispersed by wind and water. Seed production is variable from year to year but can be high, with up to 2,000 seeds per plant. Once established, Common reed regeneration and dispersal are primarily through rhizome and stolon growth. Below ground, Phragmites form dense networks of roots and rhizomes that can extend into the soil several feet. Phragmites spread by sending out rhizome runners, which can grow 10 feet or more within a single growing season. Stolon growth and seed germination occur when exposed to moist soils during times of low water. Along rivers and shorelines, fragments of rhizomes can be transported downstream, infesting new areas.
The most effective control for Common reed is by using foliar-applied herbicides. Imazapyr and glyphosate, alone or in combination, are effective at a 1.5% to 2% solution. These herbicides should be applied during the active growing season, June to September. Due to vigorous re-growth from the extensive root system, mechanical control methods, such as cutting, mowing, and fire are often ineffective when used alone, but can be effective in conjunction with herbicide application.