Phragmites

Phragmites (Phragmites australis), or the common reed, is an aggressive marsh plant that has grown in North America for over 3,000 years. However, an invasive strain of the plant introduced from Eurasia has limited growth of native phragmites and many other marsh plants that support wildlife and a balanced marsh ecosystem.

How was phragmites introduced to the Bay watershed?

Phragmites has been present in North America for over 3,000 years; however, over the past century, it has come to dominate many mid-Atlantic marshes. Scientists attribute the plant's rapid expansion to an aggressive, competitively superior genetic phragmites strain introduced from Eurasia in the 19th century via dry ballast from ships. (In the 1800s, phragmites was documented growing in places along Atlantic coastal ports where ships' dry ballast was dumped or used to fill marshes.)

Since 1910, phragmites has successfully moved into high and low marshes where the plant was once scarce. It spreads quickly, particularly in marsh areas disturbed by humans or natural events. Phragmites is now estimated to cover as much as one-third of the tidal wetland acreage in some states along the eastern U.S. coast. Only a few native phragmites populations still exist.

Why is phragmites considered to be invasive?

Phragmites reduces wildlife habitat and plant species diversity in marshes.

• When stands of phragmites grow in a marsh, they produce conditions that do not allow other plant species to grow.
• Phragmites stands commonly replace and exclude native marsh plant species, such as cordgrass and cattails, which are considered more important as food and shelter for wildlife.
• Phragmites can also threaten rare and endangered plant populations.

What is being done to manage phragmites?

Phragmites control options are limited and costly. Once established, phragmites is difficult to control. Furthermore, there are native strands of phragmites that must be preserved at the same time the introduced strain is controlled.

There have been extensive efforts to control introduced phragmites in the Bay watershed. Many watershed states are mandated to control phragmites on state-owned wildlife management areas and provide cost-sharing for private landowners that have wildlife habitat.