Russian Thistle (Sasola kali)

Russian Thistle description

Russian thistle is a large bushy plant sometimes referred to as tumbleweed.

Propagation

Annual. Seeds.

Distribution

Russian thistle is listed as noxious weeds in much of Canada, including Ontario, Manitoba, Saskatchewan, Alberta and British Columbia.

Identifying Russian Thistle

Seedling

Cotyledons narrow, grass-like, hairless, lengthening to reach 1 to 2 inches. First true leaves opposite (later alternate), needle-like, round in cross section, soft, pointed at tips, as long or longer than cotyledons.

Mature plant

Stems are erect, branched, bushy, 1/2 to 4 feet tall at maturity. Stems green, often with striped red lines, rough, with stiff hairs.



Leaves are opposite initially, becoming alternate. Young leaves soft and needle-like, up to 2 inches long. Older leaves short, stiff, lanceolate with sharp spine on tips, only 1/4 inch long, stalkless.

Root structure description

Taproot.

Flowers

Green to pink, without petals, small, in upper leaf axils. Flowers beginning early July, with mature seed by mid-August. Seed are spread when the stem breaks from the roots at maturity, and the entire plant is blown about, scattering seed.

Post senescene

The bush-like plant often turns reddish at maturity. The plant "skeletons" are often seen caught up on barbed-wire fences.