Blue Mist Shrub 'Dark Knight' (Caryopteris × clandonensis 'Dark Knight')
Zone: 5 to 9
Height: 2.00 to 3.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: July to September
Bloom Description: Deep blue
Sun: Full sun
Water: Medium
Maintenance: Low
Flower: Showy, Fragrant, Good Cut
Leaf: Fragrant
Attracts: Butterflies
Tolerate: Drought
Easily grown in average, medium moisture, well-drained soil in full sun. Prefers loose loams. Tolerates some drought. Intolerant of wet, poorly-drained soils. Roots are winter hardy to USDA Zone 5, but top growth is only reliably winter hardy to USDA Zone 7. Thus, stems will often die to the ground in the cold winters of Zones 5 and 6, with roots surviving to push up new stems in spring. Many gardeners in Zones 5 and 6 simply assume stems will be damaged in winter and automatically prune back hard all stems each year in early spring. Moreover, even in warm winter climates where the stems usually survive winter, gardeners still frequently prune the plants back hard in early spring to promote vigorous new stem growth. Flowering is unaffected by spring pruning because plants bloom on new growth.
'Dark Knight' features a profuse, shrub-covering bloom of fragrant, deep bluish-purple flowers in terminal and axillary clusters (cymes) from late summer into fall. Ovate to lance-shaped, dull green leaves (to 1.5" long) are silvery below. May be found sold under that name 'Black Knight'.