dense-flowered cordgrass

Spartina densiflora

   

Family: Poaceae

Weed Class: A

Year Listed: 2003

Native to: South American coastal regions.

Toxic: not known to be

Other Legal Listings: WA Quarantine list, WAC 16-750

additional photos

 

   

Why is it a noxious weed?

In general, the Spartina genus is considered highly invasive and one of the most aggressive worldwide. Spartina displaces native species, destroys wildlife habitat, interferes with recreational activities and is difficult and expensive to control.

How would I identify it?

General Description: Dense flowered cordgrass is a perennial salt tolerant grass that is upright in form, growing in dense tufted clumps.

Flower Description: The inflorescence is a spike, 2.4 to 11.8 inches long. The flowers are dense, compact and colorless.

Leaf Description: The blades are narrow, long and in-rolled. Blades are tough, grayish in color and 1/4 to 1/3 inch wide.

Stem Description: Culms hollow and range from 10.6 to 59 inches in height.

Fruit/Seed Description:

May be confused with:

How does it reproduce?

Unlike other Spartina species, this species reproduces only by seeds.
 

Where does it grow?

Dense flowered cordgrass grows in the upper intertidal zone, or mid to high marsh zones, near the mean high water mark, or just below it on open mud. Please click here to see a county level distribution map of dense flowered cordgrass in Washington.
 

How do I control it?

General Control Strategy

Control methods of Spartina densiflora are thought to be similar to the other Spartina species. Information presented is based on results of other Spartina species.

Mechanical Control

Seedlings can be pulled out effectively though care should be taken to remove both shoots and roots. Covering small clones with woven geotextile fabric has been successful on Spartina patens. 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.

Cultural Control

Diking can be used as a containment measure, since dikes confine the lateral spread of rhizomes. Diking blocks tidal flow, which stops nutrient flow and oxygen exchange. Prolonged flooding may eventually kill Spartina and other species that cannot tolerate standing water.

Herbicide Control

Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.


 

For more information

 
See our Written Findings for more information about dense-flowered cordgrass (Spartina densiflora).
WSDA's Spartina Eradication Program, 2013 Progress Report

Additional Photos


 
 

 


Dense-flowered cordgrass infestation

 


Dense-flowered cordgrass infestation

 


Dense-flowered cordgrass infestation

 


Dense-flowered cordgrass inflorescense

    

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