Common Smoketree Smokebush

Common smoketree (Cotinus coggygria, Anacardiaceae) is a deciduous broadleaf shrub or small tree from southern Europe to central China and the Himalayas, reaching 10 to 15 feet tall with a spread of about 16 feet. Insignificant pink to white flowers give way to masses of pubescent, hair-like pedicels and peduncles that create the famous billowing smoke effect through summer. Fall color is spectacular, ranging from orange to purple, red, and scarlet.

Common smoketree grows in full sun on well-drained soils with moderate water needs and medium drought tolerance, hardy in Zones 5a to 8b. It is deer-resistant and tolerates clay soil. It actually performs best on poor, rocky soils. Documented diseases include powdery mildew and verticillium wilt. Skin contact may cause dermatitis in sensitive individuals despite the plant being non-poisonous. Cultivars include 'Royal Purple' (12 to 15 feet, deep purple foliage), 'Golden Spirit' (lime-gold foliage, 8 feet), 'Winecraft Black,' 'Grace,' and 'Ancot.'

Smokebush is one of the lower-maintenance ornamental shrubs for the Puget Sound lowlands. Only two diseases (powdery mildew, Verticillium wilt) and zero pests are documented, which is remarkable for our region. The catch is that both diseases correlate with conditions we provide naturally: shade promotes mildew, and Verticillium persists in our soils. The solution is full sun and sharp drainage. In the heavier lowland soils, that means amending the planting hole or choosing a naturally well-drained site. Bloom starts around 501 GDD base 50. The 'smoke' effect comes from the fading flower panicles, not the flowers themselves. Purple-leaved cultivars (‘Royal Purple’, ‘Grace’) are the most popular locally. Hard pruning (stooling) in late winter produces the largest leaves and most vivid color at the expense of flowers.

— Chris Welch, ISA Certified Arborist