HARDINESS: Zones 4 to 8
PREFERRED SOIL pH: Acid
PREFERRED SOIL TYPE: Average
PREFERRED LIGHT: Sun to partial shade
ATTRIBUTES: Airy flower clusters, colorful foliage; for specimens, beds, foundations
SEASON OF INTEREST: Late spring through fall
FAVORITES: 'Velvet Cloak', 'Royal Purple', 'Purpureus', Rubrifolius group
QUIRKS: Rich or very acid soil leads to poor flowering
GOOD NEIGHBORS: Artemisia, Russian sage, dusty miller, new Guinea impatiens, coleus
WHERE IT GROWS BEST: Adapts to many climates and soils
POTENTIAL PROBLEMS: Usually trouble-free
PRUNING: Lives for decades; prune to shape plant or remove damaged branches
CRITTER RESISTANCE: Excellent
SOURCE: Nursery plants
DIMENSIONS: 10-15 ft (3-4.6 m) tall and equally wide
Smokebush in the Landscape
When allowed to follow its natural inclinations, this unusual shrub grows into a 15 ft (4.6 m) tall tree, hence the confusion between its common names of smokebush and smoke tree. But even in its treelike form, smokebush is small enough to fit in with other large shrubs or to serve as a focal point in the lawn, at the corner of a house, or near a drive or walkway. Wherever it is planted, smokebush always commands attention because of its unusual airy, rounded flower plumes, which resemble puffs of purple smoke. These plumes appear in spring and persist until fall.
Sorting out Smokebush
The species has green leaves that are often tinged pinkish bronze when young, feature a red midrib and edges through the summer, and turn yellow and red in fall. The 10 in (25.4 cm) long flower plumes are tawny green and so profuse that the shrub's leaves are barely visible.
As beautiful as the species is, many gardeners prefer the purple-leaved cultivars, such as 'Velvet Cloak', 'Royal Purple', and 'Purpureus'.The Rubrifolius group includes a variety of plants whose leaf color ranges from claret to plum. The flowers for all of them are a smoky pinkish purple, and the leaves turn red in autumn.
You can spotlight the dark leaves by pairing smokebush with high-contrast companions, such as Russian sage, artemisia, or other plants with gray foliage. Plants with golden leaves or pink flowers will also intensify smokebush. A particularly striking combination is smokebush under-planted with coleus and New Guinea impatiens that exhibit shades of purple, chartreuse, and pink.
While smokebush tolerates sites with some shade, growing it in full sun deepens the leaf colors, which provides a beautiful frame for the fluffy flower panicles. So select a site where the shrub will get plenty of light. Set out new plants in early spring and provide water during droughts the first season after planting. Because smokebush has fast-growing, fibrous roots, it becomes established quickly and is soon very drought tolerant.
Plants of any age rarely have pest problems and require no special care beyond a light application of fertilizer every spring. Use an organic or timed-release, balanced fertilizer applied at half strength according to package directions. Smokebush prefers a soil pH of 5.5-6.8. and leaf color will be poor if it grows in overly fertile or very acid soil. If necessary, neutralize the soil with garden lime in fall, applied per package directions.
When grown as a shrub, smokebush needs little pruning. Prune only to remove damaged wood or to shape the plant in spring Aggressive pruning results in long, unattractive, poor-flowering branches. You can keep shrubs compact and short by pruning back to 6 in (15.2 cm) every 2-3 years. This treatment turns smokebush into a leafy, rounded shrub. Flowering will be sparse, but no other shrub can equal the purple foliage.