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  • Noxious Weed Identification List

    Russian Knapweed


    (Centaurea repens aka Acroptilon repens)

     Info Sheet Adobe PDF Icon   

    Colorado List B - Eradication required in Jefferson County

    General

    • Family: Sunflower (Asteraceae)
    • Perennial
    • Colony-forming
    • Native to Eurasia
    • Introduced to North America in late 1800s

     

    Habitat

    • Emerges in early May
    • Full grown by June
    • Found in cultivated areas, orchards, pastures and right-of-ways

     

    PLANT

    Vegetation

    • Mature plants are 1 to 3 feet tall
    • Leaves are dark green and slender
    • Stems are erect and branched
    • Stems and leaves are covered with dense, white hairs

     

    Roots

    • Spreading, up to 8 feet deep

     

    Flower

    • Color: Lavender with papery bracts
    • Season: June to September
    • Size: ¼ to ½ inch long

     

    Seed

    • Germinate in the fall and spring
    • May remain viable in soil for more than 30 years

     

    Seedling

    • Forms dense patches
    • Rosettes form the first year and bolt early May to June of the next season

     

    Reproduction

    • Seed, spreading roots and root fragments

     

    CONTROL

    Biological

    • None

     

    Chemical

    • Apply one of the following when actively growing (spring through fall):
      • Tordon (restricted-use pesticide); or
      • Dicamba (Banvel); or
    • Apply Bloom to Post-bloom (fall)
      • Tordon (restricted-use pesticide); or
      • Escort; or
      • Telar

     

    Cultural

    • Prevention – maintain health of site

     

    Mechanical

    • Burning - N/A 
    • Grazing - Not recommended; causes chewing disease in horses 
    • Mowing - N/A 

     

    More Information

     

    Use all chemicals according to the manufacturer's label. Listing the above methods or products does not imply a specific recommendation or endorsement.



    Alicia Doran
    Weed & Pest Management Specialist
    303-271-5989
    adoran@jeffco.us

    weed-pest-b-russian-knapweed-flower

    weed-pest-b-russian-knapweed-habit


    Last Updated: 8-5-2013