SAV watershed wetland brackish

Background

Phragmites (Phragmites australis), also known as the common reed, is an aggressive wetland invader. Phragmites is a unique invasive species because the origin of the plant is uncertain. Many scientists attribute its recent rapid spread and destructive habit to a new genetic variety. Phragmites grows in temperate regions in and near fresh to brackish waters. The coarse stalks, averaging 2 to 4 meters in height, are connected to feathery inflorescences, which flower from July to October.

Phragmites is a familiar site in most wetland areas along the East Coast. Its ability to tolerate a range of conditions associated with polluted areas has allowed it rapidly to colonize new areas over the last few decades. Phragmites spreads by seed dispersion; it produces seeds in great abundance. It also spreads through the reproduction of its root system. The roots grow laterally, creating dense, thick mats.

The Problem

• Phragmites stands dominate wetlands, reducing wetland diversity.
• Phragmites provides little to no shelter for resident wildlife.
• The dense roots can alter the hydrology of wetlands by trapping sediments, causing a drying effect.
  

The Solution

Phragmites can be controlled using a variety of chemical and harvesting methods. Chemical treatments include spraying and using wipe-on herbicide (wicking), but these methods cannot guarantee complete eradication. Other methods of controlling phragmites include dredging, seasonal mowing, the use of plastic barriers and burning. Controlled burning is a quick and efficient method that reduces biomass and increases soil nutrients. Often a combination of methods will yield the best results. Total eradication of phragmites may not be possible, nor is it the most desirable outcome. In some areas the presence of phragmites strengthens dikes and roads and reduces beach erosion. Phragmites rhizomes can provide food for waterfowl, and the plant provides habitat when its stands are interspersed with open water or other vegetation.

Phragmites photo courtesy: U.S. Fish and Wildlife Service

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Last modified: 06/12/02