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Onopordum acanthium
Also called Scotch Thistle, Scotch Cotton Thistle, Heraldic Thistle, Giant Thistle, Scotch Cottonthistle, Scottish Thistle, Woolly Thistle
Cotton thistle is a spiny, silver-grey biennial thistle that forms a large rosette in its first year and a tall, branched flowering stalk in its second. Grow it in full sun in well-drained, dry soil, and remove it before it seeds since it spreads readily.
Onopordum acanthium (cotton thistle, Scotch (or Scottish) thistle) is a flowering plant in the family Asteraceae. It is native to Europe and Western Asia from the Iberian Peninsula east to Kazakhstan, and north to central Scandinavia, and widely naturalised elsewhere, with especially large populations present in the United States and Australia. It is a vigorous biennial plant with coarse, spiny leaves and conspicuous spiny-winged stems.
It should not be confused with Cirsium vulgare (spear thistle), which is also known as Scotch or Scottish thistle and is the national flower of Scotland. Spear thistle is native to Britain, while cotton thistle is non-native.
Cotton thistles are native to Eurasia. The plant prefers habitats with dry summers, such as the Mediterranean region, growing best in sandy clay and calcareous soils which are rich in ammonium salts. It grows in ruderal places, as well as in dry pastures and fields. Its preferred habitats are natural areas, disturbed sites, roadsides, fields, and especially sites with fertile soils, agricultural areas, range/grasslands, riparian zones, scrub/shrublands valleys and plains along with water courses. Temperature and moisture, rather than soil nutrient concentrations, determine the ecological performance of Onopordum species.
It is grown as an ornamental plant for its bold foliage and large flowers. It has been used to treat cancers and ulcers and to diminish discharges of mucous membranes. A recent study of a crude extract from the leaves of the plant demonstrated activity against glioblastoma, a type of very malignant brain tumor. The receptacle was eaten in earlier times like an artichoke. The cottony hairs on the stem have been occasionally collected to stuff pillows. Oil from the seeds has been used for burning and cooking.
Illyrian cottonthistle · Reticulate Thistle · Bull cottonthistle
Text excerpted from the Wikipedia article Onopordum acanthium by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
