The knapweed genus includes four useful garden perennials -- Centaurea dealbata, Centaurea hypoleuca, Centaurea macrocephala, and Centaurea Montana -- all resembling the popular annual bachelor's buttons. The genus derives its name from a species, which, according to mythology, was used to cure the foot of a Greek centaur called Chiron.
Description of knapweed: Knapweed has large leaves; the usually stout-stemmed plants bear thistlelike flowers. Ease of care: Easy.
Growing knapweed: Knapweeds like full sun and any good garden soil that is dry and well drained.
Propagating knapweed: By division or by seed.
Uses for knapweed: Grouped in the border or set throughout the garden, these flowers are bright and cheerful, bearing attractive seed heads.
Knapweed related species: Centaurea dealbata, or the Persian knapweed, bears bright, rose-purple flowers typical of the genus that bloom over a long period on 2-foot stems. The coarsely cut leaves are gray and hairy underneath and green on top. Plants sometimes need staking. Centaurea hypoleuca blooms from June to August with 2- to 3-inch flowers of rich rose on 18-inch stems. Leaves are green above and silvery white beneath. The seed heads are very attractive. Centaurea macrocephala has no common name. The plants have large, coarse leaves with stout stems often reaching 4 feet in height. The blossoms are bright yellow and resemble thistles. They make good cut flowers and are excellent when dried. They only bloom for a short time. Centaurea montana, or the mountain bluet, has cornflower-blue flowers that bloom over a long period on 18-inch stems. Young foliage is silvery white.
Scientific name for knapweed: Centaurea species