The most imposing of the several thistles we cultivate at The Cloisters, the stately cotton thistle has a presence that appeals to modern sensibilities. The silvery-white leaves are deeply cut and very handsome: the species name acanthium denotes their resemblance to the foliage of the acanthus. Some value cotton thistle as an ornamental in contemporary gardens, although others consider Onorpordum acanthium to be a weed. (A weed is a plant you don’t want, while an herb is a plant with a use. Many of the plants we grow in the gardens of The Cloisters are considered weeds in our time and place, but were herbs in the Middle Ages.) Once the purplish-pink flowers of the cotton thistle have withered, it is important to remove the heads so that the many seeds do not disperse to the four winds and colonize the world.
It would be difficult to credit the use made of the cotton thistle in the past if we didn’t have the authoritative testimony of the great sixteenth-century herbalist John Gerard: the down was collected from the spiny leaves and used by the poor to stuff mattresses and pillows. (Those who were better off had bedding stuffed with feathers, but Gerard cautions that some upholsterers cheated and mixed the down gathered from thistles in with the pricier goose down.)
Onopordon acanthium was and is a heraldic plant: also known as Scotch thistle, it is the national emblem of Scotland. A hanging embroidered with thistles was included in the inventory of royal property made at the death of James III in 1458, and the Scots poet William Dunbar’s poetic allegory “The Thrisell and the Rose” celebrated the marriage of James IV of Scotland and Princess Margaret of England in 1503. (Maude Grieve, A Modern Herbal, 1931.)
Cotton thistle is a biennial; a plant grown from seed produces a rosette of leaves in the first year and sends up flowering stalks in the second year. Once it flowers and sets seed, the plant dies. Onopordum is an easy plant to cultivate, but it is a plant of stony ground, and it does have a tendency to fall over when grown in a soft bed in a garden, especially when the heavy flower heads form. Next year, I’m going to try putting a goodly amount of pea gravel into the planting hole to give the roots something to hold on to, in the hope that the tall and top-heavy thistle won’t have to be staked when it matures.
More thistles on Monday.