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    The Hawkweed Consortium will be meeting at the 2010 Invasive Species in Natural Areas Conference in Idaho.  More details coming soon!

    NEW! Montana Hawkweed Identification Bulletin now available.  To order more copies, contact Montana State University Extension Publications by clicking here.

     

  • resources

    Check out our resources page with many guides, fact sheets, and regional maps to help you identify the hawkweed complex. 

       

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    Established in 1948 as the Europe Station of the Commonwealth Institute of Biocontrol, CABI Europe-Switzerland has traditionally worked on the classical biological control of invasive insect pests and weeds of Eurasian origin, on behalf of the temperate areas of the world, particularly North America, Australia, and New Zealand.

     

  • Check out our Hawkweed Gallery

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    hawkweed biocontrol consortium

    natives

    Identifying native hawkweeds from invasive hawkweeds can be complex.  Wilson (2006) recognizes fourteen native hawkweeds in western North America.  The flower heads of native hawkweeds are practically identical to invasive hawkweeds and consist of numerous strap-shaped ray flowers with notched tips.  All native hawkweeds have yellow flowers besides one species which has a white flower. The inflorescence tends to be elongated and more open.  Native hawkweed rosettes tend to have broader near-oval leaves and short simple hairs.

    Narrowleaf hawkweed, a native hawkweed in North America.
    Narrowleaf Hawkweed, a native hawkweed in North America.

    The number and size of leaves on the flowering stem of native hawkweeds is an important distinguishing characteristic for identification.  Native hawkweeds tend to have more numerous leaves along the length of the stems although they get smaller as they progress upward.

    hybridization

    All invasive hawkweeds in North America are polyploid (n=9) and typically asexual, compared to the entirely diploid and sexual native species.  Hybridization between invasive and native hawkweeds most likely is not possible.  However, hybridization between invasive polyploid hawkweeds could be possible but to date is not scientifically documented.