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Chehalis River Cooperative Weed Management Area

Program Contact: Grays Harbor County Weed Board
(360) 482-2265

The goal of a Cooperative Weed Management Area program is to promote cooperative efforts to manage invasive plants and work toward desired plant communities at the watershed level.

A group of concerned land managers and noxious weed boards began meeting over 18 years ago to work together on Washington’s second largest river system and it’s weed problems. Together, a plan for weed work in this system has been developed.


Some invasive plants of concern: Brazilian elodea, parrotfeather, Japanese knotweed, purple loosestrife, and spartina in the tidal basin.

Grant projects have included: parrotfeather surveying, purple loosestrife control , B. elodea control, and knotweed control.

Thurston County Weed Board

Thurston elodea project

Spartina in the Harbor

Grays Harbor County has 2 different types of invasive Spartina – Spartina alterniflora and Spartina densiflora. Spartina alterniflora is found in lower tidal areas and has been very problematic in Willapa Bay. Spartina densiflora has been found in very limited supply in upper tidal areas near Ocean Shores. In 2006 a Grays Harbor Spartina Task force formed in hopes of preventing further infestation.

spartina brochure

click to view larger image

Egeria densa – click to view larger