Phragmites

Phragmites australis. Aquatic plant line drawing is the copyright property of the University of Florida Center for Aquatic Plants (Gainesville). 

Phragmites (Phragmites australis) is an aggressive-growing, exotic emergent plant that is infesting Michigan’s coastal areas, wetlands, and lake shores. Plants can exceed 15 feet in height and obstruct shoreline views and uses. Phragmites can greatly reduce the diversity of desirable native plants, including the native variety of Phragmites, and reduce wildlife habitat.

Phragmites is a perennial plant that is dormant during the winter months. Primary growth occurs during mid-summer with flowering and seed dispersal in late summer and fall. Besides seed dispersal, Phragmites can also spread through the expansion of underground stems called rhizomes. In fact, much of the plant’s biomass is underground. Rhizomes can exceed 60 feet in length, grow several feet per year, and readily grow into new plants when fragmented. Phragmites roots can penetrate the ground several feet and the plant can survive in relatively dry uplands as well as shallow wetlands. However, water depths greater than a few inches typically inhibit Phragmites seed germination. Mechanical cutting, prescribed burnings and herbicide treatments can all be used to control Phragmites. Herbicide treatments are the primary control method and appear most effective when applied later in the growing season. To be effective, prescribed burning should only be considered the year after the plants have been treated with herbicides. To avoid soil disturbance, mechanical cutting should only occur when the site is dry enough or when the ground is frozen. Regardless of method, Phragmites is difficult to completely eradicate and will likely require integrated, long-term maintenance control. Professional assistance may be required to differentiate between the native and the exotic variety of Phragmites, and to implement proper control methods.

Some municipalities have adopted ordinances or are considering ordinances to facilitate Phragmites control, and some lake communities are conducting treatments financed through special assessment districts. For more information about Phragmites visit:

www.michigan.gov/deq/0,1607,7-135-3313_3681_3710-178183--,00.html

Most of the above information was derived from a publication entitled “A Guide to the Control and Management of Invasive Phragmites.” This publication was co-authored by representatives of the Michigan Department of Natural Resources, the Michigan Department of Environmental Quality, Ducks Unlimited, the U.S. Fish and Wildlife Service, the Michigan Department of Transportation, and the U.S. Army Engineer Research and Development Center.