The spidery, tubular petals on mountain bluet (Centaurea montana) bring sprinkles of blue to your perennial garden, and its vigorous green foliage adds bold texture all season.
Mountain bluet is easy to grow, but it can get invasive in very rich soil. Planted in more difficult soil, though, it thrives where other perennials might struggle. Mountain bluet is attractive in naturalized areas and cottage gardens, where its robust growth is an asset. Cultivars like ‘Amethyst in Snow' (pictured) give you more color choices, blooming in pink or white.
Common name: Mountain bluet, perennial bachelor's buttons, perennial cornflower
Botanical name: Centaurea montana
Plant type: Perennial
Height: 14 to 18 inches tall, depending on cultivar
Zones: 3 to 9
Family: Asteraceae (Daisy family)
- Sun: Full sun to part shade
- Soil: Well-drained
- Moisture: Moderate but consistent
- Fertilizer: Usually none required
- Mulch: Place a thin layer of organic mulch around new plantings to deter weeds.
- Pruning: Cut stems of spent flowers to the ground.
- ‘Amethyst in Snow' (pictured) has flowers with white, fringed petals and deep purple centers. The foliage is silver-green. This 2006 introduction prefers alkaline soil and flowers mid-May to mid-June. Grows 14 inches tall. Zones 3 to 9.
- ‘Caerulea' has blue flowers. Grows 18 inches tall. Zones 3 to 9.
- ‘Carnea' has pink flowers. Grows 18 inches tall. Zones 3 to 9.
- f. alba has pure white flowers in spring and summer, set off by gray-green foliage. Grows 18 inches tall. Zones 3 to 9.
- ‘Gold Bullion' has chartreuse foliage and blue blooms. Grows 18 inches. Zones 3 to 8.
- Blooms are attractive in cut-flower arrangements.
- Good companions for mountain bluets include lupines and catmint.
- If planted in favorable conditions and trimmed after the first flowering, it will flower again later in the season.
- Plant in large groupings for a good show of color.
- Place where plants won't sit in wet soil over winter.
- Rust, mildew, stem rot, aster yellows, and thread blight may attack the plant.
- Start seeds in late summer.
- Divide every four to five years in spring or fall.
All in the family
- Some of the most familiar members of the daisy family include fernleaf yarrow (Achillea filipendulina), silver mound artemisia (Artemisia schmidtiana), cosmos (Cosmos bipinnatus), and blazing star (Liatris spicata).
Text by Mary Pestel, photo courtesy of Blooms of Bressingham, www.bloomsofbressingham.com.