Learn how to grow centurea or mountain bluet.
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This late spring blooming perennial flower has been looking beautiful this year. It goes by a number of common names such as mountain bluet, perennial bachelor’s buttons, and corn flower. I know it mostly by its botanical name, Centaurea montana.
This European native is popular in English cottage gardens and across our region. It produces blue, white, or burgundy colored, spider-like blooms. It grows 2 to 3 feet tall and can flop over, so is best grown in groups and caged to stay vertical. Centurea does spread by underground rhizomes and self sows readily. In late summer we do a bit of digging and dividing to keep it in bounds and thin out seedlings in spring.
While the blue flowers are traditional there are a number of newer varieties with interesting color variations. ‘Black Sprite’ has purple-black flowers on dwarf 14 inch tall plants. ‘Amethyst in Snow’ is also short, and has white petals surrounding a deep purple center. ‘Gold Bullion’ has blue flowers with golden colored foliage providing interest even when the plant isn’t in bloom.
Centurea grows best in full to part sun on well-drained soil. It tolerates a hot, dry location, but flowers best with plenty of moisture in the soil. It’s one of the easiest perennials to grow and great for novices. Plant centurea with other late spring flowering perennials such as iris, geranium and peony. The flowers are bee and butterfly magnets and are great for use as a cut or dried flowers in arrangements. After flowering in spring, cut back the plant by 2/3rds to let it regrow and flower again in summer.
From the Connecticut Garden Journal