Smooth Cordgrass
Spartina alterniflora
Washington State Classification
Class A — Eradication Required Statewide
It displaces native species, destroying habitat and food sources for fish, waterfowl and other marine life.
Quick Reference
Identification
Growth Habit
Smooth cordgrass is a rhizomatous, perennial grass and is 2 to 4 feet tall. The plant is deciduous; its stems die back at the end of each growing season.
Leaves
The blades are 1/4 to 3/5 inch wide. Ligules consist of a fringe of hairs.
Flowers
The flowers are inconspicuous and borne in a congested spike which is 2 to 3 inches long.
Impact
It displaces native species, destroying habitat and food sources for fish, waterfowl and other marine life. It also interferes with recreational activities and is difficult and expensive to control since it is located in areas that are hard to access.
Ecology & Spread
Habitat
Smooth cordgrass is found growing in the intertidal zone, where it colonizes mud- or sandflats in saline or brackish water. Please click here to see a county level distribution map of smooth cordgrass in Washington.
Spread Mechanisms
Reproduction
Smooth cordgrass can spread by seed, rhizome, or vegetative fragmentation.
"
Control Methods
Mechanical
- Seedlings can be pulled out effectively but care should be taken to remove both shoots and roots. Covering small clones with woven geotextile fabric has been successful on Spartina. Mowing infestations can contain growth, limit seed set and eventually kill the plants. To be effective, clones must be mowed repeatedly, beginning with initial spring green-up and continued until fall die-back. In some cases, repeated mowing will be required for three or four years.
Biological Control
- Several insects feed on Spartina in its native range. More research is needed before biocontrols can be introduced in Washington.