American smoke tree is a tall shrub to small tree usually 6–16 feet tall, with slender, spreading branches and aromatic, resinous sap. It may attain a height of 33 feet.
Leaves are simple, alternate, most abundant toward the twig tips, 1½–6 inches long, 2–3½ inches wide, broadest in the middle and tapering at both ends, or obovate (egg-shaped with the narrow part at the base); tip round to blunt, base broadly wedge-shaped or rounded, margin entire or somewhat wavy; upper surface bluish green or olive green and smooth to hairy; lower surface hairy early and smooth with age, veins conspicuous; leaf stalk ¼–2 inches long, yellowish green to reddish, smooth or hairy; bruised leaves somewhat fragrant.
Bark is gray to black, roughly breaking into thin scales that are longer than broad; wood orange to yellow, sapwood creamy white, coarse-grained, soft, light.
Twigs are slender, green to reddish or purple when young, gray and smooth with age; pores small, abundant, pale.
Flowers in May, greenish yellow, borne in loose, few-flowered clusters at the end of stems, clusters 5–6 inches long, 2½–3 inches broad; flower stalks with feathery, gland-tipped hairs and purplish flowers about ⅛ inch across, petals 5; stamens 5. The “smoke” from smoke tree is often mistaken for a spray of flowers, but what you are seeing is actually the hairy, colorful stalks of the flowers after the blossoms have fallen away.
Fruits June–July, small, hard-cased drupes (a seed covered by fleshy pulp) ⅛–¼ inch long, kidney-shaped, flattened, smooth, pale brown; fruit stalk slender, conspicuously purple or brown with gland-tipped hairs.
Similar species: The Eurasian smoke tree (Cotinus coggygria) is commonly sold in garden centers as a landscaping ornamental. It is not native to North America. It is typically smaller, with smaller, more oval leaves and showier flower clusters. At least one popular variety of the Eurasian smoke tree has purplish leaves.