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saltmeadow cordgrass (Spartina patens)

ODA rating: A and T

Salt meadow cordgrass risk assessment
Noxious weed listing process

Oregon saltmeadow cordgrass Distribution
Other common names
salt marsh cordgrass

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  Images courtesy of Tom Forney, Oregon Dept. of Agriculture. 

If images are downloaded and used from the ODA web site please be sure to credit the photographer.
S. patens is a rhizomatous perennial grass 1 to 4 feet tall with very narrow leaf blades 0.5-2 mm wide. The leaves and flowering stems are deciduous being replaced each year.  Leaf color is light green, often in contrast to the colors of native tufted hairgrass and sedges. The dark-colored flowering panicles are not taller than the leaves. Infestations grow slowly outward forming patches easily spotted from the air. Reproduction occurs by the release of root fragments during storm events or by seeding. Salt-meadow cordgrass is similar to common cordgrass (S. anglica), smooth cordgrass (S. alterniflora), and dense-flowered cordgrass (S. densiflora). A detailed key is recommended for positive identification.

Esturine habitats are some of the most limited and threatened habitats in Oregon. In most bays over 90% of the original marshes have been filled, diked and developed.  Spartina species are important salt marsh species to bays and estuaries of the east coast. The associated fauna is adapted to and dependent on spartina grasses for shelter and food production. The physical makeup of west coast salt marshes and bays differs by being dominated with extensive areas of open sand and mudflats with smaller areas of marsh. Once established, east coast Spartina alter this balance of marsh to mudflat by converting most of the mudflat to high marsh, effecting feeding areas, nursery areas, migratory bird resting sites, and shellfish production areas. Spartina patens can dominate and exclude all native vegetation from the high marsh causing serious reductions in waterfowl food production and plant species diversity. At Cox Island, the rare Sidalcia hendersonii is directly threatened by Spartina encroachment.

Spartina patens is native to the salt marshes of the Atlantic seaboard and the Gulf coast of the United States. It is also found on the eastern shores of Mexico and Central America.  Currently populations occur in North America in the known locations: in British Columbia one population near Naniamo, Washington near Hoodsport, Oregon near Florence, and in California at San Francisco Bay.  Native to the eastern coast of the United States, Spartina patens was introduced into Oregon as packing material for oysters.

Distribution in Oregon
Salt-meadow cordgrass is the only  known to occur in Oregon in one known location. The historic site is at Siuslaw Bay, Cox Island. Known to exist on the island since the 1930's. It is currently under management by The Nature Conservancy, the Cox Island site is under active treatment.

Biological controls
Biological control agents are not used on "A" listed weeds in Oregon. This weed is being managed for eradication.

Informational Links
Oregon WeedMapper