Onopordum: Scotch thistle, cotton thistle

Height 1.8m (6ft)

Planting distance 75cm (30in)

Flowers mid to late summer

Rich or ordinary garden soil

Sunny or partially shaded site

Hardy biennial

Scotch thistle (Onopordum acanthium) makes an excellent specimen plant in a border, large shrubbery or wild garden. It is grown for its dramatic foliage — broad silver-grey spiny leaves covered with white cobweb-like hairs – though purple thistle-like flowers do appear from mid to late summer.


Sow the seeds directly in the flowering site and thin to 75cm (30in) apart. If the plants are to reach their maximum size (1.8m/6ft tall), they should be grown in rich soil. However, ordinary garden soil in full sun or partial shade still gives good results. Remove dead flowers to prevent self-seeding.

Pests and diseases

Trouble free.

22. February 2012 by Dave Pinkney
Categories: Annuals, Biennials, Bulbous Plants, Featured Articles | Tags: , , , | Comments Off on Onopordum: Scotch thistle, cotton thistle


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