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Hybridization Strategy and Guidance for Golden Paintbrush and Harsh Paintbrush

Triptych of golden paintbrush, a hybrid, and harsh paintbrush

(Photos by Tom Kaye, Institute for Applied Ecology)

  • Importance in Implementing this Hybridization Strategy

    Hybridization with harsh paintbrush (Castilleja hispida), one of the preferred host plants for the endangered Taylor’s checkerspot butterfly, poses a potential threat to the threatened golden paintbrush (C. levisecta), another species of conservation emphasis.

    To minimize the potential for hybridization, the U.S. Fish and Wildlife Service, the Washington Department of Natural Resources and the Washington Department of Fish and Wildlife entered into a Memorandum of Understanding to adequately manage this threat to golden paintbrush, while harmonizing conservation efforts for both golden paintbrush and Taylor’s checkerspot butterfly. We developed a Hybridization Strategy and Guidance document to outline a landscape level, long-term strategy for outplanting golden paintbrush to support its conservation and outplanting harsh paintbrush to support Taylor’s checkerspot butterfly conservation.

    The primary goals are:

    1. To communicate the issue of hybridization as a potential threat to golden paintbrush

    2. To outline solutions necessary for the long-term protection of golden paintbrush and the use of harsh paintbrush as a larval host plant for Taylor’s Checkerspot Butterfly in WA.

    3. To provide specific information on sites, geographic areas, and proximity guidelines needed to implement the outlined solutions.


    Memorandum of Understanding

    Available here (PDF- 552 KB)

    Hybridization Strategy and Guidance Document (July 2021)

    Available here (PDF- 5.2 MB)

    Video of Hybridization Strategy presentation (MP4- 144 MB)

    Overview of recommended solutions:

    Prevent Prevent hybridization in other geographic areas
    Implement Implement a decision-making framework
    Manage Actively manage sites with both paintbrush species or those that are hybridized
    Map Map the golden and harsh paintbrush distribution and refine active inventory
    Adopt Adopt decontamination procedures for multi-site prairie restoration activity
    Formalize Formalize seed production risk management
    Disseminate Disseminate information
    Improve Improve understanding of hybridization risk and its impact to species


    PDF Maps of Regions

    North Puget Lowlands (Island & San Juan Counties)

    Olympic Peninsula (Clallam and Jefferson Counties)

    South Puget Lowlands (Mason, Pierce, and Thurston Counties)

    Southwest Washington (Clark, Cowlitz, and Lewis Counties)

    Willamette Valley, Oregon


    Outplanting Proposals

    If you are planning to outplant either golden paintbrush or harsh paintbrush and need to have your proposal reviewed (see Hybrid Guidance a Strategy document for decision flow charts), please use this form below.  Please send proposals to

    Please anticipate 30-90 days for proposal review.

    Proposal Review Form


    If you have questions about the Hybridization Strategy and Guidance, proposal submission and review process, or MOU, please contact:

    Erin Gray
    Endangered Species Biologist
    U.S. Fish and Wildlife Service

    Hannah Anderson
    Wildlife Diversity Division Manager
    Washington Department of Fish and Wildlife

    Joe Rocchio
    Program Manager, Natural Heritage Program
    Washington Department of Natural Resources

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