Blue spirea is a low, mounding, deciduous shrub in the Lamiaceae (mint) family. It is a hybrid cross between C. incana and C. mongholica . The common name blue mist refers to the flowers which have a fluffy cloudlike appearance. This light airy shrub quickly reaches an average size 2 to 3 feet tall and wide and has a medium to fine texture. When there is little else blooming in the garden in the late summer and early fall this plant will delight with its bright blue fragrant flowers that attract butterflies, bees, and other pollinators. In cold climates below zone 6 the stems will die back to the ground. Plant in loose, well-drained loamy soil in the full sun. Too much fertilizer will result in lanky growth. Cut it back in late winter to improve its form and remove dead stems as the blooms appear on new growth. It is very easy to transplant, tolerant of drought, is pest and disease resistant, and is seldom browsed by deer. Plant this shrub in groups or mass planting along shrub borders or use as a low growing hedge. Its fragrant foliage and nectar-rich flowers make it a wonderful addition to a cutting, sensory, or pollinator themed garden. Quick ID Hints : Axillary inflorescences Flowers have a beard at base petal Insects, Diseases, and Other Plant Problems: No serious problems. Crown rot may occur in poorly drained soils. More information on Caryopteris .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day)
Soil texture
Loam (Silt)
Soil drainage
Good Drainage
Available space
3 feet-6 feet
Mature size
Height: 2 ft. 0 in. - 3 ft. 0 in. | Width: 2 ft. 0 in. - 3 ft. 0 in.
Growth rate
Medium
Maintenance
Medium
Canopy layer
3 - Shrub (3-15 ft)
Form & Appearance
Texture
Fine
Foliage
Deciduous
Leaf color
Blue; Gray/Silver; Green
Leaf type
Simple
Leaf arrangement
Opposite
Leaf shape
Ovate
Leaf margin
Entire; Serrate
Leaf value
Fragrant
Leaf size
1-3 inches long
Hairs present
No
Leaf detail
Opposite, simple, dull blue-green leaves; 1-2 in. long; whitish below; no fall color; fragrant when crushed. Ovate, half as wide, acute, entire or serrate, muted blue-green above and silvery and tomentose on underside. The pubescent petiole is 1/3" long.
Flower color
Blue
Flower value
Fragrant; Good Cut; Showy
Flower form
Cyme
Flower detail
Bright blue flowers in late summer. Axillary cymes on the uppermost leaves. Bright blue, base petal is elongated like a beard.
Bloom time
Summer
Stem color
Gray/Silver; Green
Stem detail
4 sided, grayish green, flat nodes, pubescent.
Wildlife & Ecology
Native status
Unknown
Wildlife value
Flowers attract butterflies, bees, and other beneficial insects.
Attracts
Butterflies
Landscape Use
Landscape theme
Butterfly Garden; Cottage Garden; Cutting Garden; Drought Tolerant Garden; Garden for the Blind; Pollinator Garden