PREVENT

Acroptilon repens

Family: Asteraceae (Sunflower).

Other Scientific Names: Centaurea repens.

Other Common Names: Turkestan thistle, mountain bluet, creeping knapweed.

Origin: Eurasia.

Growth Form/Reproduction: Perennial. Vegetatively from rhizomes; seeds.

Legal Status: Weed Control Act, Forest and Range Practices Act.

Impacts:
Agricultural: Can infest cultivated fields, grain and alfalfa crops and pastures. Toxic to horses.
Ecological: Russian knapweed forms dense stands that can displace native species and reduce forage production. Russian knapweed may contain allelopathic compounds that inhibit the growth of other plant species.
Human: No information available.

Habitat: Adapted to a wide range of soil conditions in low- to mid-elevation grasslands and forests. Disturbed sites, roadsides, grasslands, riverbanks, irrigation ditches, pastures, clear cuts, and cropland.

Status and Distribution: Not reported in the CIPC area.

Management Strategy: Mechanical control (cutting) will not kill this species, but repeated cutting before the plant bolts reduces vigor. Picloram, clopyralid, and 2,4-D, used either alone or in combination can provide control. A combination of cutting and herbicides can manage Russian knapweed but treatments may need to be repeated over several years; in autumn. Apply picloram to plants that have re-emerged following cutting.