Humboldt/Del Norte Weed Management Area

WMAs are local stakeholder groups working on weed projects. Typically, they are organized by county, through county Agricultural Commissioners' offices. All interested land management entities, public and private, are invited to participate. Official WMA partners sign a Memorandum of Understanding indicating their commitment to working on invasive plant problems to the extent resources allow. Each WMA develops a strategic plan that identifies their top priorities for local management. Together these partners plan and implement projects on-the-ground, and collaborate on mapping and public education. 

California's WMAs have proven to be an efficient and effective instrument for controlling the spread and impact of invasive weeds throughout the state. The program has grown to include (from CDFA program report) 48 WMAs covering all 58 counties. Because they are local efforts that involve all land management stakeholders, their work has strong local support.

Humboldt/Del Norte WMA

Outreach Summary:



  • Weed Awareness Week
  • Volunteer work days
  • Table at the County Fair
  • Board of Supervisor Proclamations


  • The Humboldt/Del Norte WMA (HDNWMA) has recently started a Lend a Weed Wrench program through which the public may check out weed wrenches at public locations to work on their own private property.

Project Highlights:

  • Purple loosestrife eradication
    • This project is is in the 2-mile river corridor of the Eel River Watershed in Humboldt County. The goals are to protect both riparian water quality and threatened and endangered anadramous fish habitat. The purple loosestrife eradication integrates manual and herbicide methods. Project partners include California State Parks, Humboldt County, US Fish & Wildlife Service, California Department of Food and Agriculture, California Department of Fish and Game, and U.S. Forest Service.
  • Meadow knapweed containment
    • Meadow knapweed can be found in Humboldt County in the Weitchpec area. In Del Norte County this weed can be found in and around Crescent City, along Forest Service routes, and around five acres of a wilderness trailhead. This project exemplifies a bi-county, early detection and treatment approach to managing an A-rated pest, meadow knapweed. The spread of meadow knapweed is being addressed at an early stage to protect habitats and high-value sites such as pasture land, oak woodland communities, riparian areas, river bars, a botanic area, designated wilderness, and designated Wild & Scenic Rivers. This project deliberately engages multiple stakeholders in the management of meadow knapweed on all fronts. The project integrates manual hand pulling and grubbing, weed cloth, weed whacking, Waipuna hot foam treatment, revegetation, and herbicide use. Project partners include U.S. Forest Service, Mid-Klamath Watershed Council, CalTrans, California Department of Food and Agriculture, Del Norte County Agricultural Commission, Yurok Tribe, and Bureau of Land Management.
  • Hardinggrass control in the Bald Hills prairies
    • The Bald Hills prairies offer an excellent example of perennial grassland, comprised of a diverse mix of both native and exotic species but not dominated by any single exotic grass. Harding grass is well documented for overtaking grasslands and creating large monocultures over time. By preventing the extensive spread of Hardinggrass in the Bald Hills prairies, HDNWMA will preserve the unique assemblage of native plants, preserve high quality elk habitat, help prevent widespread establishment of Hardinggrass on neighboring lands, and preserve the pre-historic and historic landscape. There are 50 acres of Hardinggrass in the Coyote Creek drainage in Bald Hills, Humboldt County. The main method of control for eradicating Hardinggrass from the area are herbicides. Project partners are National Park Service, California Department of Food & Agriculture, and Humboldt Del Norte WMA.
  • Future work
    • The HDNWMA is focusing on regional collaborations to eradicate the knotweeds in Humboldt and Del Norte County; including Himalayan, Japanese, and Giant knotweeds. Two projects are being proposed with Base and Supplemental 2009 funding from CDFA to support (a) an ongoing eradication effort in the Mattole Watershed, and (b) a new eradication project in the lower Klamath River watershed.




Contact Humboldt/Del Norte Weed Management Area

Jennifer Wheeler
Bureau of Land Management, Arcata Office
1695 Heindon Road
Arcata, California  95521
Phone: 707-825-2316


Service Area

Services provided in:
  • Humboldt County, California

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