Musk Thistle

Appearance

Musk thistles may grow as an annual, winter annual, or biennial. The typical musk thistle exhibits itself first in the form of a rosette, a cluster of tightly packed leaves laying flat on the ground which vary in diameter from a few inches to three feet. By mid to late May the plants bolt (sending up flowering stems) and soon after bloom.

MuskThistleFlower_thumb.jpg

Each flower head, depending on the size, can produce anywhere from 200 to 3,000 seeds by midsummer and an entire plant can produce more than 10,000 seeds. Musk thistle heads are distinguished by their "powder puff" shape. Other Kansas thistles have "shaving brush" shaped heads. Musk Thistle is also known as the nodding thistle.

Control

Methods include: Hand cutting - cut between the first appearance of pink and the first appearance of brown on the earliest head. Hand digging - dig the root at least two inches below ground level and remove all soil.

Removal

  • Burying - Pick heads that are beyond the bud stage and place in a tight container. Avoid scattering seed. 
  • Burning - When burning heads, make sure the heads and seeds are destroyed; burning wet or green heads may leave viable seed.
  • Mowing - Mow cleanly and closely and repeat as needed for satisfactory control. Mowing shall be approved first by your County Noxious Weed Department.
  • Biological Control - Two insects are approved for control but shall be approved first by your County Noxious Weed Department and the State Board of Agriculture.
  • Chemical control - numerous herbicides have been approved, contact us for a complete list.

Treatment

Recommended herbicides are available at the Pratt County Noxious Weed Department on a cost-share basis. For more information regarding this noxious weed you can either contact our office, or the County Weed Directors Association of Kansas, or go to the Kansas Department of Agriculture Noxious Weed Control Website.