Common reed flower cluster. Courtesty: U.S. Army Corps of Engineers

Common Reed (Phragmites australis)

Alternate common name: Phragmites, Tall Reed.
Appearance: Grows from to 5 to 15 feet high, in dense stands. The reed is light green in the spring and summer, changing to light brown in the fall. Blooming flower clusters are purple or tan, changing to light brown with age. Flower stalks remain over winter.
Habitat: Fresh to brackish marshes, more common along the coastline.
Seasonal appearance: Blooms in August.

Description

The common reed is a tall, stately member of the grass family. This species stands 5 to 15 feet tall, blooms in August, and produces large red-purple plume-like flowers, usually 6 to 12 inches long. As they age, the flowers turn light silvery brown and feathery. The mature flowering bodies are present on the reed until the next flower blooms during the following year. The leaves of the common reed are smooth, flat, and green and can grow as large as 20 inches long and 2 inches wide. In the fall and winter, the reed is distinctively light brown in color, with the featherlike flowering plume still intact.

Life History and Growth

The common reed grows by sending out rhizomes, long root runners that are widely spread out underground, ranging from 17 to 34 feet from the plant. These runners sprout frequently, producing large colonies of reeds. Common reed is often found adjacent to cattails, and can be an aggressive colonizer of salt marshes that have been separated from the sea.

Though common reed occurs naturally in the upland zone of many Rhode Island marshes, habitat alteration by development and construction can alter marsh hydrology and allow common reed to invade other areas of the marsh, replacing other marsh grasses.

A stand of common reed growing along the edge of a salt marsh. Courtesy: NOAA

Special Notes

• Common reed has replaced smooth cordgrass and salt hay grass in extensive areas of tidal marsh. These altered marshes do not support as many different species as unaltered cordgrass marshes.
• Dense thickets of common reed can also create a fire hazard because they are so dry and densely packed. Marsh restoration efforts are often targeted in areas where common reed is abundant.

Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.