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Special Projects

The Mason County Noxious Weed Control Program has secured funding from partners such as the Washington State Department of Agriculture (WSDA), Washington State Noxious Weed Control Board, United States Department of Agriculture, Forest Service, Washington State Department of Ecology, Bonneville Power Administration, Washington State Parks, and others to complete special projects. Projects involve citizen engagement, survey, documentation, and treatment. Supplemental funding from grants and agreements is a key element of noxious weed education, inventory, and control efforts in Mason County.

If you have questions regarding any of these projects, please contact the program at or (360) 427-9670 ext. 592.

Ongoing Projects

Knotweed Control

Since 2008, the Mason County Noxious Weed Control Program has completed control of knotweed in riparian and near-shoreline areas on behalf of community members. Currently, the program receives funding from the Washington State Department of Agriculture to complete knotweed survey and control on Coulter Creek, Mission Creek, Little Mission Creek, Finch Creek, Stimson Creek, Sherwood-Anderson Creek, and in the town of North Bay and Allyn. WSDA funds are used for acquiring landowner contacts; completing survey/inventory work and control measures; and documenting knotweed infestations within all systems previously worked.

The Mason County Noxious Weed Control Program is a member of the Olympic Invasive Working Group (OIWG), a loose-knit consortium of about 20 government agencies, tribes, non-profits, and private landowners, all working to eliminate invasive knotweed from waterways on the Olympic Peninsula. Clallam County Noxious Weed Control Board (CCNWCB), as the unofficial group leader, coordinates the meetings and supports the work of other group members. Visit the OIWG’s website for more information, including presentations and comprehensive annual reports.

Giant Hogweed Eradication

In 2000, WSDA identified 11 giant hogweed (Class A noxious weed) sites in Mason County, four of which were found along US Highway 101 and the remaining being ornamental escapees predominantly in the Hoodsport area. Since 2000, 87 giant hogweed sites have been found, 36 of which are presumed to have active infestations.

Since 2007, MCNWCB has prioritized documentation, control, and eradication of giant hogweed. Grant funding from the WA State Weed Board and WSDA supplements county resources to support surveys for giant hogweed, initiate property owner contacts, and provide control assistance.

Perennial Pepperweed Control

In 2018, Mason County Noxious Weed Control Board (MCNWCB) staff identified perennial pepperweed (Lepidium latifolium), a Class-B Designate noxious weed, growing along the Hood Canal shoreline at Belfair State Park. This was the first documented infestation along the Hood Canal, and since then several other infestations have been found. All infestations are documented on WSDA’s IForm database. MCNWCB estimates that perennial pepperweed continues to infest less than 10 acres in the county since the first documentation at Belfair State Park.

In addition to funding provided by a contract with Washington State Department of Agriculture, Department of Natural Resources Aquatic Invasive Species Program (DNR AIS) have provided Washington Conservation Corps crew assistance for the control of known perennial pepperweed infestations on, and adjacent to, their lands.

WA State Parks Survey & Control

Since 2007, the Program has intermittently collaborated with WA State Parks on noxious weed control activities, including at Lake Isabella, Hope Island, Belfair, and Potlatch State Park. In 2023, staff surveyed and controlled priority noxious weeds such as meadow knapweed, spurge laurel, and perennial pepperweed at a handful of parks, including Lake Isabella and Belfair State Park.

Olympic National Forest – Mason County & Hood Canal Ranger District Cooperative Noxious Weed Control

Since 2005, Title II funding has provided MCNWCB supplemental funding to develop a Noxious Weed Control Program responsive to the needs of the Mason County community. Funding provides employment for several local residents and training opportunities to staff, partners, and volunteers. This long-standing partnership with the Forest Service allows the program to be an active participant in the protection of National Forest lands from the threat of invasive species.

On federal lands, the project implements the Olympic National Forest Integrated Weed Management Program. Olympic National Forest personnel develop an annual Planned Treatment List which identifies known infestations, or key areas, targeted for control. Survey and control of noxious weeds is prioritized along roads, trails, campgrounds, and public and private gravel pits. These areas serve as primary vectors for new weed invasions between land ownerships and into lands previously uninfested by invasive weed species.

Read more about the Olympic National Forest Invasive Plant Program.