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Species
Information
- smooth
cordgrass
- Spartina
alterniflora Loisel.
- USDA
Symbol: SPAL
- Oregon
Noxious Weed Designation: A,T
- Pictures
ALERT: PLEASE CALL 1-866-INVADER IF YOU SUSPECT YOU HAVE FOUND THIS SPECIES
Identification:
Perennial aquatic grass. Grows 0.5 to 2.5 ft tall. Leaf (blade) flat, loosely in-rolled at tip, 1/8 to 1 in wide at base. Blade at a 15-35 degree angle to stem. Internodes are fleshy. Inflorescence slightly open, branches loosely erect to ascending and loosely overlapping. Rhizomes long and fleshy, 1/8 to 1/4 in in diameter. Smooth cordgrass is similar to common cordgrass (S. anglica), salt-meadow cordgrass (S. patens), and dense-flowered cordgrass (S. densiflora). A detailed key is recommended for positive identification. One historic Oregon site was eradicated from the Siuslaw estuary in 1997. The largest west coast infestations are in San Francisco Bay, CA and Willapa Bay, WA.
Impacts: Smooth cordgrass is the most dominant non-native cordgrass species in the Pacific Northwest. Inhabiting the lowest intertidal zones in estuaries, this species poses the greatest threat to mudflats crucial to clam and oyster production. Mono-cultures of this corgrass trap sediments, raising the elevation of infested areas several feet. Thousands of acres of mudflats in the PNW, critical to migratory waterfowl are at risk of invasion. This plant alters estuary hydrology and ecosystem functions through increased sedimentation and accretion.
Biological
Controls: Biological control agents are not used on "A" listed weeds in Oregon. If this weed is found in the state it will be managed for eradication or containment. One approved biological control agent, a planthopper, is successfully established in California and Washington.
Oregon
Maps of Smooth Cordgrass Distribution
Links:
USDA
Plants Database information on smooth cordgrass
GRIN
Database information on smooth cordgrass
Oregon Department
of Agriculture information on smooth cordgrass
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