Canadian Thistle
Description
- An aggressive perennial with a vigorous root system that continually produces new shoots, invading new areas and outcompeting other vegetation types.
- Grows 2 – 5 feet tall.
- Leaves are alternate, lance shaped, irregularly lobed, and have wavy spiny/toothed margins.
- Stems are usually smooth, but sometimes have short hairs and are slightly grooved.
- Flowers are purple and pink, occasionally white, and are borne at the end of the stems in clusters.
- Buds are 1/2 inch wide by 3/4 -1 inch long, have a tear-dropped shape, and lack spines.
- This plant is a prolific seed producer and also spreads by roots.
- Seedlings emerge as small rosettes in the fall or early spring, eventually bolting into erect branched flowering stems. Flowers begin to develop in late June, blooming between July and August.
- This plant is most recognizable in mid-July when flowers change to seedheads with obvious white fluffy tops. Seeds are attached to the “fluff” and can become airborne and spread to new areas.
Habitat
Found growing in a wide range of habitats. Typically infests a variety of disturbed landscapes and is commonly found along roadsides, trails, natural areas, pastures, forest and field margins, mining locations, waste areas and unmaintained gravel pits. This plant establishes quickly after new road construction, housing and development projects, overgrazing of pastures, forestry clear-cuts, and destructive flooding events