The Mighty Phragmites

Phragmites australis, also known as common reed, is a tall invasive bamboo like grass found in wet areas. Although Phragmites can provide some cover for wildlife, it often forms large stands, which out-compete native plants, leading to a reduction in plant and wildlife species. In disturbed wetlands that may have once been occupied by bayberry, elderberry, hibiscus and switchgrass before Phragmites introduction, will often become occupied by a single species, Phragmites, once introduced.

The exact rate Phragmites is spreading in Delaware and Maryland is unknown. However, it is increasing in abundance and distribution as more soil is disturbed through development. Although Phragmites can spread by seed, it most commonly spreads by creeping rhizomes (underground roots), and stolons (above ground roots) that can extend 15'+ in a season. 

Phragmites Control
While it is possible to control Phragmites with physical treatments such as mowing and flooding, it is rarely an effective option for large stands with existing trees or shrubs. Based upon our experience and research the most practical method of controlling Phragmites is through the application of herbicides approved for aquatic use by the U.S. Environmental Protection Agency. When used according to instructions, the broad spectrum aquatic herbicides are virtually nontoxic to mammals, birds, and fish.
Herbicides applied to the foliage of actively growing plants, are rapidly absorbed throughout the plant: leaves, stems, and rhizomes. Absorption is especially important in the control of Phragmites due to the rapidly expanding stolons, and rhizomes.

Phragmites are most successfully treated while plants are actively growing and are in bloom. Plants are generally most susceptible from July through the first hard frost of winter. In large stands, aerial spray equipment (helicopter with spray boom) is the most cost effective. While, wetland edges lize ATV and truck mounted sprayers to get the best coverage possible, in wetland areas with mixed vegetation, a backpack sprayer may be the only option.

 Dead Phragmites cane should be left on site to prevent spread by seed during removal to adjoining areas. In heavily infested areas some regrowth may occur from unconnected rhizomes. In addition, seedling growth may occur. For best results, the some area should be sprayed in two successive years, then spot-treated in succeeding years to prevent reestablishment.

Methods

Phragmites will show signs of stress within a few weeks but, often take 6 to 8 weeks to turn brown. Phragmites should be left standing until the new year, when they can be cut. While cutting is not necessary, it is often desired to enhance views and promote the establishment of native plants.

Cut phragmites should be left on site to prevent  spread to adjacent areas by seed. All infested areas will have some regrowth and should be spot-treated for up to three consecutive years to prevent reestablishment. Controlling phragmites in wetlands by any method in Maryland will require advance approval by state and federal agencies before treating.