Spear Thistle

The tall and striking Spear Thistle comes into flower across The Lizard from July.

Photo: © Natural England/Peter Roworth

Scientific name: Cirsium vulgare

Other common names: Bull Thistle, Scotch Thistle, Common Thistle

What to look for:

  • Family: Asteraceae (Daisy family)
  • Flowers: Each plant holds a few downy flowerheads, about 2 to 5 cm in length; spiny green bracts, purple florets.
  • Leaves and stem: The stems are hairy with prickly, stalkless, deeply lobed leaves; there is also a basal rosette of larger spiny, down-covered leaves.
  • Height: 30 to 150 cm tall.
  • Where: Native to Europe, including the UK; found on grasslands, open woodlands, verges and disturbed land.
  • When: Blooms from July to October.
  • Habit: Upright, branching.

The Spear Thistle is not just tall above-ground. It also has a long tap root, making it awkward to remove if it takes up unwelcome residence in your garden. In the wild, however, it is both vibrant and stately, reaching heights of up to five feet, capped by the purple-pink flowerheads, beloved of pollinators, that appear from July to September. Goldfinches love the seeds, hanging on to the swaying stems while they probe for their tasty treats.

It’s not just those purple flower tops that are striking, though. Look closely at the green spiny bracts and you’ll see a ball of spikes delicately threaded through with down.

It seems a shame that the Spear Thistle, which is a native plant here, is classified as a noxious weed in Britain. It does spread easily, though, and is a good coloniser, often turning up in disturbed, man-made habitats. Neither has its status as a weed harmed its wild distribution in the country.

The Spear Thistle spreads by seeds, which are released as the flowerhead ages, dries out and splits open. New plants flower in the second year after germination. The plant dies back after the seeds have dispersed.

Did you know…?

…The Spear Thistle is the thistle species most likely to be the Scotch Thistle, Scotland’s national flower.

…This species has been introduced to Australia and parts of the United States, where it is considered an invasive weed.

More information and references:

Mabey, R., 1997. Flora Britannica. Chatto & Windus, London.

Rose, F. and O’Reilly, C., 2006. The Wild Flower Key, 2nd edition. Frederick Warne, London.

Stace, C., 2010. New Flora of the British Isles, 3rd edition. Cambridge University Press, Cambridge.

Published: June 2015
Author: Amanda Scott
Photos: Top and middle – © Natural England/Peter Roworth
; lower – Amanda Scott