Russian Knapweed Information

(Centaurea repens)

Extremely persistent, perennial forb.

Habitat:
            *Prefers open areas in semi-arid environments
            *Roadsides
            *Riverbanks, riparian forests and irrigation ditches
            *Rangeland, pasture, and disturbed grassland
            *Clear-cuts and wasteland
            *Cropland

Flowers:
            *Solitary
            *Urn-Shaped
            *.33-.50" diameter

Seeds:
            *Up to 1,200 per plant
            *Germination temperature range: 68-86 degrees
            *Viability: 2-8 years (soil)           
            *Dispersal: Passive (hay, feed, animal fur etc.)

Roots:
            *Taproot
            *Lateral growth: 6-8 feet per year
            *Two years growth can cover 120-150 square feet

Growth and reproduction:
            *Reproduction primarily from rhizomes
            *Shoots arise from adventitious buds along rhizomes
            *Individual stands can survive and grown for 75 years or more

Management:
            *Prevention is most effective control
            *Cutting, dicing and mowing several times per year will deplete carbohydrate reserves and 
             inhibit seed production
            *Herbicides: clopyralid, clopyralid + 2, 4-D, glyphosate, picloram
            *Fall applied picloram is most effective

Threats:
            *Aggressively competes for light, nutrients, and water
            *Allelopathic
            *Rapidly forms monocultures eliminating biodiversity of fauna and flora
            *Causes "chewing" disease in horses