Written by Industry Expert Richard Ruby III, Aquatic Biologist
Plants become classified as invasive species when they invade areas outside of their native range, upset the natural community they have invaded and cause considerable damage to either the ecology or economy of an area. Phragmites australis, or common reed, is a plant that most definitely meets all of these criteria. Native to Europe and Asia, invasive Phragmites is an aggressive colonizer of a variety of wetland habitats across the United States. Once established, the nuisance plant’s growth habits allow it to quickly outcompete most native species, ultimately creating a dense monoculture which reduces species richness and overall habitat value. As a result of these invasive characteristics, Phragmites has become a significant threat to freshwater and coastal wetlands across the country.
Whether managing established Phragmites colonies or endeavoring to prevent its introduction, it is critically important to understand the plant’s methods of reproduction and dispersal. Phragmites is spread through several means, called vectors. The natural reproduction of Phragmites is accomplished in three ways: by seed, rhizome fragmentation and the use of stolons. Seeds can be spread by the wind, wetland birds, surface currents and wave action as well as on recreational and construction vehicles. Expansion through the development of stolons (lateral vegetative growth of the stem), also allows for very rapid spread of the infestation. Rhizomes, the underground root structures of the plant, when fragmented through land disturbance or other natural processes such as erosion, have the potential to become re-rooted in any suitable area they are deposited. ATVs and construction vehicles can also be vectors of rhizomal spread if the root debris is not removed when leaving a Phragmites infested area.