Spotted Knapweed

( Centaurea stoebe )

QUICK IDENTIFICATION

  • In early stages of growth, gray-green leaves are deeply lobed with short, thin, grayish hairs
  • A single pink to purple flowerhead at the end of stems; bracts at the base of flower fringed with short hairs and black on the tips
  • Height up to 6 feet

Video Information

Weed Pictures

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Weed Information

Type Information
Toxicity Toxic to humans and animals. Spotted knapweed contains sesquiterpene lactones, a class of chemicals that can cause allergic reactions and toxicity in grazing animals if consumed in large quantities.
Control Hand pulling or digging using gloves, biological, herbicide and mechanical. Contact your County Weed District or local applicator for more information.
Habitat Rangelands, disturbed areas, meadows, pastures, roadsides and sandy or gravelly floodplains
Root Taproot
Leaf Shape Rosette leaves deeply lobed, while mature leaves are linear.
Lifespan Biennial or short-lived perennial
Priority 2B Weed Abundant in Montana and widespread in many counties.
Similar Looking Plants Canada thistle, diffuse and Russian knapweeds
Important Information Plants are suspected to contain toxins that inhibit the growth of neighboring plants (called catechin). Seeds remain viable in the soil for up to eight years.
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