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  • Noxious Weed Identification List

    Purple Loosestrife


    (Lythrum salicaria)

    Info Sheet Adobe PDF Icon 

    Colorado List A - Eradication required in Jefferson County

    General

    • Family: Lythraceae
    • Introduced from Europe
    • Has been sold as an ornamental but no longer available in Colorado

     

    Habitat

    • Perennial forb
    • Infestations are found in wetlands; displaces native species; Reduces waterfowl habitat
    • Prefers a moist, organic soil but tolerates a wide range of soils
    • Prefers sun but tolerates up to 50 percent shade

     

    PLANT

    Vegetation

    • Mature plants are 6 to 8 feet tall
    • Narrow leaves attached closely to the stem

     

    Roots

    • Tap root with woody lateral branches

     

    Flower

    • Color: rose-purple on spike-shaped inflorescence
    • Season: June to September
    • 2 to 3 million seeds per year

     

    Seedling

    • Germinates in spring

     

    Reproduction

    • Seed
    • Cut stems
    • Root fragments

     

    CONTROL

    Biological

    • Not allowed; eradication is required

     

    Chemical

    • Apply one of the following during flowering stage (late summer; remove flower heads before spraying):
      • 2,4-D (Aquatic); or
      • Glyphosate (RoundUp, Rodeo); or
      • Garlon

     

    Cultural

    • Prevention – maintain health of site
    • Hand pulling young plants before seed set

     

    Mechanical

    • Burning - N/A 
    • Grazing - N/A 
    • Mowing - Not recommended; will spread seed and plants resprout 

     

    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

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    Last Updated: 8-5-2013