Description
Onopordum – Onopordon – Cotton Thistle – Scotch Thistle –
There are about 40 species of erect, rosette forming biennial in this genus. They occur from steppes, stony slopes, fallow fields, and disturbed ground in Europe, the Mediterranean, and Western Asia. Thistles have simple to pinnatifid or pinnatisect, spiny toothed leaves covered in cobweb like, soft gray hair, the leaves are held alternately on coarse, usually freely branching, mostly white woolly stems, the leaf bases often continuing down the stems as very conspicuous wings. Large, round flower typically thistle like (globose with a dense tuft of purple florets at the top and covered in spiny bracts, are borne either singly or in tight clusters ate the stem tips in mid summer. They may be bright purple, blue, violet, rose pink, or occasionally white, and attractive to bees and butterflies. In the first year the plants form an attractive foliage clump with few flowerheads. In the second year they grow rapidly to full height, flower heavily then die. They readily self seed and may be grown in a large border, or in a semi wild or gravel garden. The seeds are often eaten by goldfinches.
Grow in any fertile, well drained, neutral to slightly alkaline soil in full sun shelter from strong wind.
Prone to slugs and snails, and caterpillars.
O. nervosum – O. arabicum – This tap rooted, rosette forming biennial from Portugal and Spain grows 9′ feet tall and 3′ feet wide. It produces oblong-lance-shaped, pinnatisect, spiny toothed, silver gray leaves, to 20″ long, the have prominent pale veins and are sparsely hairy beneath. In the second year, it bears massive, branching, broad winged, deeply veined, densely hairy, yellow tinged stems, in summer, these bear clusters of round, thistle like, bright purple-red to purple-pink flowers, to 1 ½” across, encased in spine tipped bracts.
Zones 7-9
