There are about 200 species of biennials and perennials, in this genus. They occur in a variety of habitats in Northern temperate regions, including grassy mountain slopes, stream sides or moorland meadows, and dry or moist alpine and subalpine meadows. They have spiny leaves and bear heads of tubular, purple, red, yellow or sometimes white flowers. Many are invasive, spreading by means of rhizomes, or self seeding. Those listed here are useful border plants or suitable for damp meadows in a wild garden.
Grow in moist but well drained soil in full sun. Dead head to prevent self seeding. Divide perennial from autumn to spring.
Prone to powdery mildew and rust.
C. japonicum – This clump forming biennial or perennial from Japan grows 3-6′ feet tall and 2′ feet wide. It produces oblong-obovate, pointed, deeply lobed to pinnate, spiny, toothed, mid to dark green leaves, to 12″ long. In late summer and early autumn it bears thistle like, rose-pink to lilac flowers, 2″ across.