In July to late August, bluebeard (Caryopteris x clandonensis) blooms with feathery, light blue, aromatic flowers. Its gray-green leaves and stems are also scented and add attractive contrast to dark green foliage. This mound-forming shrub is part of a group called “subshrub” or “dieback shrub.” Where hardy, stems tend to die back in winter, while the roots stay alive, similar to perennials. In spring, new stems grow from the roots, and flowers bloom on the current year’s growth.
Common name: Bluebeard, blue-spirea, blue-mist shrub
Botanical name: Caryopteris x clandonensis
Plant type: Aromatic, deciduous shrub
Height: 2 to4 feet tall
Zones: 5 to 9, depending on cultivar
Family: Verbenaceae (Verbena or Vervain)
- Sun: Full sun to light shade
- Soil: Well-drained, loose soil
- Moisture: Tolerates moderately dry conditions; dislikes wet sites
- Fertilizer: Apply a balanced fertilizer such as 10-10-10 once a year in late winter. Excessive fertilizer may cause vegetative growth and fewer flowers.
- Mulch: Apply a thin layer of mulch in winter to protect roots.
- Pruning: Prune stems in late winter—just the tips or nearly down to the crown, depending on the amount of dieback.
- Sunshine Blue (pictured) has chartreuse leaves and amethyst blue flowers. Foliage color is better in a sunny site. Zones 5 to 9.
- ‘Azure’ has bright blue flowers. Zones 5 to 8.
- ‘Blue Knoll’ has blue flowers and silver-gray foliage. Zones 6 to 9.
- ‘Dark Knight’ has deep blue-purple flowers and silvery gray leaves. Zones 6 to 9.
- ‘Kew Blue’ has dark blue flowers and gray-green leaves with silver-gray undersides. Zones 6 to 9.
- ‘Longwood Blue’ has violet-blue flowers and silvery-gray leaves. Zones 5 to 9.
- ‘Worcester Gold’ has yellow foliage that turns chartreuse in summer and pale lavender-blue flowers. Zones 6 to 9.
- Tolerates dry areas similar to its native habitat—the dry slopes and woodlands in the mountains of East Asia.
- Usually grows 2 to 3 feet tall, unless there’s little or no dieback, and then it can reach 4 feet tall.
- Good companions include goldenrod (Solidago spp.), sneezeweed (Helenium autumnale), salvia cultivars such as Salvia x sylvestris ‘Rose Queen’, and cushion spurge (Euphorbia polychroma).
- Group together several bluebeards in a shrub border for an attractive mass of color.
- Draws butterflies and bees to the garden.
- No serious pest problems.
- Root softwood cuttings in late spring.
- Root greenwood cuttings in early summer.
All in the family
Closely related to the Lamiaceae (mint) family, Verbenaceae includes herbs, shrubs, and trees that frequently have four-sided twigs and/or aromatic foliage. Other plants in the Verbenaceae family include beautyberry (Callicarpa americana), shrub verbena (Lantana spp.), blue vervain (Verbena hastate), and chasteberry (Vitex agnus-castus).
Text by Mary Pestel, photo courtesy of Proven Winners, www.provenwinners.com.