Distinguishing Features and Behaviors

Phragmites australis is a tall, stately member of the grass family. This species stands five to fifteen feet high and produces large purple or tan plumelike flowers six to twelve inches long that bloom in August. As they age, the flowers turn light brown and feathery.


The mature flowering bodies are present on the reed until the next flower blooms the following year.  The leaves of Phragmites are smooth, flat and green; they can grow as large as 20 inches long and two inches wide.
 

Phragmites grows by sending out rhizomes — long root runners that spread underground outwards of 17 to 34 feet from the plant. These runners sprout frequently, producing large colonies of reeds and are often found adjacent to cattails.

Field Markings
The reed is light green in the spring and summer; light brown in the fall. Flowers are purple or tan, changing to light brown with age. Flower stalks remain over winter. Size: grows in dense stands 5 to 15 feet tall. 

Habitat
Fresh to brackish marshes; more common along the coastline

Seasonal Appearance
Blooms in August

Sensitivity level to Humans
High

The Phragmites most often seen in Rhode Island is not native and can be an aggressive colonizer of salt marshes. In many areas, it has replaced other tidal marsh grasses. Recently, a native species of Phragmites has been identified. This reed is generally found in less dense patches than the non-native reed and is identified by the bare stems of the previous year’s growth. The non-native reed retains its leaf sheaths.

 

Relationship to People


Phragmites, or Phrag, as it’s commonly called, is found everywhere in the world except for parts of Polynesia. It occurs naturally in the upland zone of many Narragansett Bay marshes, forming a line between fresh and brackish water.

Following alteration by development and construction, Phragmites can take over a marsh, with its root system actually drying out the marsh.

Because cordgrass needs a wetter, undisturbed habitat to survive, Phragmites stands have replaced cordgrass in extensive areas of tidal marsh and coastal wetlands. Altered marshes where Phragmites has taken over, do not support as many different species as undamaged cordgrass marshes. Dense thickets of dried-out reeds can also create a fire hazard. Marsh restoration efforts often target areas where Phragmites is abundant.