Smoketree, American

The American Smoketree (Cotinus obovatus) is native to the SE United States, from Tennessee south to Alabama and west to eastern Texas closely related to the sumacs (Rhus). It is a larger plant, frequently becoming a small tree between 10 to 15 feet tall, with a trunk from 8 to 14 inches in diameter. The growth habit of large shrub or small tree is dependent upon soil fertility where in fertile soil it can grow to a small to medium sized tree of 30 to 40 feet tall with an open, round crown . Often classified in Rhus in the past, they are distinguished by the leaves being simple (not pinnate) and the ‘smoke-like’ fluffy flower heads.

The LEAVES are deciduous, alternate, simple oval shape, entire margin, blunt-tipped, 3 to 5 inches long; blue green above, paler below (some cultivars have variable colors and shapes). The leaves are larger than Rhus. The smoke tree also has varied but very bright fall color, usually brighter than Eurasian species of The LEAVES are deciduous, alternate, simple oval shape, entire margin, blunt-tipped, 3 to 5 inches long; blue green above, paler below (some cultivars have variable colors and shapes). The leaves are larger than Rhus. The smoke tree also has varied but very bright fall color, usually brighter than Eurasian species of Cotinus and can be quite stunning in the landscape.and can be quite stunning in the landscape.

The FLOWERS are clustered in large open terminal panicles 15–30 cm long with a fluffy grayish-buff appearance resembling a cloud of smoke over the plant, from which the name derives. They are small, greenish yellow occurring on many finely branched, slender clusters; changes color from yellowish to pink as the age; few actual flowers occur.

The FRUIT is a small drupe with a single SEED. Light brown, 1/8 inch long, kidney-bean shaped; few appear on the slender branched, hairy stems.

The TWIGS are moderately stout, reddish green, glaucous, turning gray-brown with age; buds small, leaf scar lobed.

The BARK is initially light gray-brown, later splitting into thin strips and becoming scaly and darker.

Cultivation is best in dry, infertile soils, which keeps the growth habit more compact and also improves the autumn color; when planted in fertile soil, they become large, coarse and also tend to be short-lived, succumbing to verticillium wilt disease.

The smoke trees, particularly C. coggygria, are popular garden shrubs. Several bronze or purple-leaved cultivars of C. coggygria are chosen as they have warm pink inflorescences set against purple-black foliage; the most common in commerce are ‘Notcutt’s Variety’ and ‘Royal Purple’.