Latin Name: Cirsium arvense
Alternative Name(s): Californian Thistle, Canada Thistle, Creeping Thistle
Known Hazards: None known.
Habitat: Arable land, roadsides etc, a common weed of cultivated land.
Edibility Rating: 2 (1-5)
Medicinal Rating: 2 (1-5)
Physical Characteristics: Flowers: Many small flowers (florets) in heads 1.5–2.5 cm long; petals 12–18 mm long; female flowers scented. Flowers summer and autumn.The flowers are hermaphrodite (has both male and female organs) and are pollinated by Bees, flies, Lepidoptera (Moths & Butterflies), beetles. The plant is self-fertile.Erect perennial thistle to 1 (rarely to 1.5) m high. Stems ridged, smooth, hairless to slightly hairy. Leaves lanceolate in outline, upper surface dark green and variably hairy, lower surface white woolly to hairless; basal leaves in a rosette, leaves to 15 cm long and to 4 cm wide, margins wavy to toothed, narrowing to the base; stem leaves to 7 cm long, lobed, not on a stalk and base continuing down stems for a short distance. Seeds light brown to olive, smooth, finely longitudinally grooved.
Distinguishing features: Distinguished by creeping roots; spiny leaves; flowerheads 0.7–2.0 cm wide in panicles; florets all tubular, mauve, arising from a receptacle with bristle-like scales, male and female flowers on separate plants; bracts around heads soft, tips gradually pointed to short spined; seeds 2.5–4 mm long, compressed, topped by bristles 20–25 mm long.
Dispersal: Spreads by seed and creeping roots.
Root of first year plants – raw or cooked. Nutritious but rather bland, they are best used in a mixture with other vegetables. The root is likely to be rich in inulin, a starch that cannot be digested by humans. This starch thus passes straight through the digestive system and, in some people, ferments to produce flatulence. Stems – they are peeled and cooked like asparagus or rhubarb. Leaves – raw or cooked. A fairly bland flavour, but the prickles need to be removed before the leaves can be eaten – not only is this rather fiddly but very little edible leaf remains. The leaves are also used to coagulate plant milks etc.
Antiphlogistic; Astringent; Diuretic; Emetic; Emmenagogue; Hepatic; Tonic. The root is tonic, diuretic, astringent, antiphlogistic and hepatic. It has been chewed as a remedy for toothache. A decoction of the roots has been used to treat worms in children. A paste of the roots, combined with an equal quantity of the root paste of Amaranthus spinosus, is used in the treatment of indigestion. The plant contains a volatile alkaloid and a glycoside called cnicin, which has emetic and emmenagogue properties. The leaves are antiphlogistic. They cause inflammation and have irritating properties.
Oil; Tinder. The seed fluff is used as a tinder. The seed of all species of thistles yields a good oil by expression. The seed of this species contains about 22% oil.
Notes: Grows in cooler months, dying back in autumn to re-shoot from root buds. Forms large colonies with dense growth crowding out desirable plants. Weed of pastures, crops, roadsides and wasteland in higher rainfall areas, particularly in Victoria and Tasmania.