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Plumeless Thistle


Carduus acanthoides - Asteraceae Family - Biennial

spiny_plumeless_thistle_1_tile   spiny_plumeless_thistle_2_tile  spiny_plumeless_thistle_3_tile  spiny_plumeless_thistle_4_tile


  • Flowers: Flower heads are red-purple in color and can span up to 1 inch. Flower stems are branching with spiny wings extending to the flower head.
  • Seeds:  Seeds are oblong, striated, and slightly curved. They are mainly wind-dispersed and can remain viable in the soil for up to 10 years. Plumeless Thistle spreads entirely by seed.
  • Leaves: The leaves of the basal rosette are 4-8 inches long and have spiny teeth. The stem leaves are alternate and attach directly to the stem. They are sparsely hairy underneath.
  • Flowering Time:  June through August.
  • Life cycle:  Plumeless Thistle is a biennial, meaning it produces a basal rosette in its first season with the stems and flowering bodies coming the season after. It flowers and disperses seeds from early to mid-summer.   


  • Plumeless Thistle is unpalatable to livestock and can greatly reduce an area’s forage potential if allowed to spread. 
  • Thistle fragments and spines may injure livestock and humans moving through infestations.
  • Dense stands of thistles can greatly impede recreational activities, hinder grazing livestock, and obstruct wildlife from access to water.
  • Plumeless Thistle forms thick monocultures which can greatly reduce the biodiversity in an area. 


Most effective control methods

  • Prior to flowering, small infestations can be effectively controlled by hand pulling or digging while being careful to ensure the removal of the entire root system. Mowing and cutting plants can also be effective if done prior to seed production.
  • Several herbicides are useful for managing this weed, if applied in the fall when the plants are in their seedling or rosette stage.

    Large Images


    Gary L. Piper, Washington State University,

    Plumeless thistle: flower



    Todd Pfeiffer, Klamath County Weed Control,

    Plumeless thistle: rosette



    Gary L. Piper, Washington State University,

    Plumeless thistle



    Todd Pfeiffer, Klamath County Weed Control,

    Plumeless thistle: foliage and flower



    Steven Katovich, USDA Forest Service,

    Plumeless thistle: stem and foliage



    Bruce Ackley, The Ohio State University,

    Plumeless thistle: seeds



    Loke T. Kok, Virginia Polytechnic Institute and State University,

    Plumeless thistle: infestation



    Todd Pfeiffer, Klamath County Weed Control,

    Plumeless thistle


    • Plumeless Thistle Fact Sheet

    • References

      Agriculture Victoria. (2016, June 20). Plumeless thistle (Carduus acanthoides). Retrieved from

      Colorado State University. (2015, July). Plumeless thistle identification and management [PDF file]. Retrieved from View PDF

      Colorado Weed Management Association and the Center for Invasive Species and Ecosystem Health. Spiny plumeless thistle (Carduus acanthoides). Retrieved from

      Minnesota Department of Agriculture. Prohibited – control noxious weed: Plumeless thistle – carduus acanthoides L. Retrieved from

      Moechnig, M. (2016, April 8). Plumeless thistle (Carduus acanthoides). Retrieved from

      University of Nebraska – Lincoln Extension. (2010, January). Plumeless thistle [PDF file]. Retrieved from View PDF