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Russian knapweed (Rhaponticum repens)

Russian knapweed (Rhaponticum repens)

Description: Russian knapweed is a deep-rooted perennial that was introduced in the 1800s and is toxic to horses. It is 2'-3' in height with branched, hairy stems that are ridged, and numerous.

Life Cycle: Herbaceous perennial

Habitat: Waste places or dry-land areas.

Leaves: Hairy. Lower leaves deeply indented. Upper leaves short, narrow, and smooth edged.

Flower: White, pink, or lavender disk flowers with heads surrounded by small leafy bracts up to 0.5" in diameter.

Fruit: Gray or yellow smooth seeds.

Root: Deep and extensive rhizomes, can be allelopathic.

The problem is…Russian knapweed persists in cultivated fields when established and produces deep roots.

The scientific name has been reclassified as Rhaponticum repens.

Russian knapweed seedling,  L.L. Berry.

Russian knapweed mature plant, Steve Dewey.

Russian knapweed, Steve Dewey.

Russian knapweed stem, L.L. Berry.

Russian knapweed flowers, Norman E. Rees.

Russian knapweed flower, Rob Routledge.