Canada Thistle

Ojibway: Mazaanaatig
Latin: Cirsium arvense (L.) Scop.Canada-Thistle-1

Common Names

  • Creeping thistle
  • Noxious thistle
Description

Numerous fragrant pale magenta or lavender flower heads top this highly-branched, smooth-stemmed plant.

Flowers

Heads 2.5 cm (1 in.) wide, all disk type, heads surrounded by spine-tipped bracts; June to October.

Leaves

12.5-20 cm (5-8 in.) long, grey-green with matted hairs, spiny, lanceolate, deeply cut, wavy-edged, mostly stalkless.

HeightCanada-Thistle-2

30-150 cm (1-5 ft.) tall.

Habitat

Pastures, roadsides, waste places.

Range

Throughout North America, except much of far north and southeastern United States.

Discussion

This species was introduced to Canada from Europe, hence the common name ?Noxious Thistle.? Its smaller flowering heads and non-spiny stem distinguish it from the Bull Thistle (C. vulgare). This plant has a variety of uses, the root is used as a tonic, diuretic, astringent, and hepatic. It is also chewed for a treatment for toothache, and the seed fluff is useful as tinder for starting fires.