Plumeless thistle was introduced into North America in the late 1800s from Eurasia (Ball et al, 2006). It is a biennial tap-rooted thistle that grows up to 2 metres tall. The upper stems are branched and have spiny wings extending right up to the flower head. Flowers form at the top of the stems in clusters or singlets. The flowers are typically purple in color, although some are white/cream. This plant is often confused with Nodding thistle (Ministry of Agriculture, Lands and Fisheries, 2002).

Plumeless thistle has been known to hybridize with Nodding thistle when found inhabiting the same location (Ministry of Agriculture and Lands, 2002).

Biennial forb

They prefer mid-elevations where they are often found inhabiting pastures, fields, logged areas, and roads sides (Ministry of Agriculture, Lands and Fisheries, 2002).

This thistle is one of the more aggressive thistles resulting from its heavy seed production. A single plant can produce up to 9,000 seeds and seeds can remain viable in the soil for up to 10 years. Seeds spread predominantly by the wind.

Sites have been confirmed in Williams Lake along the Williams Lake River Valley Trail (Not on Maps). It is thought to occur in the North Cariboo as well but this has not yet been confirmed.