American smoketree provides an unexpected treat with its unusual, billowy hairs reminiscent of puffs of smoke. With a pleasing habit, easy care and outstanding fall color, it's a plant that deserves wider recognition.
I first saw the American smoketree, Cotinus obovatus, growing in the gardens of the New England Wildflower Society, Garden in the Woods, Framingham, Mass., in the mid 1990s. I was awestruck by its beauty when I looked upward through the canopy of oval-shaped overlapping leaves - casting just enough shade to cool a fatigued hiker and enough filtered sunlight that annual flowers could bloom under it. This was an early summer visit and the tree was not in bloom, nor did it have its famed fall color. It was beautiful just as it was. I knew I needed to learn more about this tree.
Photo courtesy of Christopher Upton
The little-known American smoke-tree is native to the southern United States, from Georgia to Tennessee, south to Alabama, and west to Kentucky and Texas. It also will grow perfectly well in the mid-Atlantic region and even as far north as Ontario, Canada. It is very uncommon in the wild, being mostly restricted to isolated stands. I have been a Washington, D.C., resident since the early 1960s and do not recall seeing this tree in any area landscape or for sale in garden centers, nor do I recall seeing it grown in any of the nurseries in which I worked. I did note its European relative, Cotinus coggygria, but the American smoketree is in some ways more attractive.
Large, open terminal panicles sport small, greenish yellow to greenish white flowers that change color from yellowish to pink as they age. Top of page, American smoketree's showy fall color can range from yellow to orange to red to purple.
Photos courtesy of Barbara Bullock unless otherwise noted.
Seen against a brilliant blue sky, American smoketree foliage is a knockout.
An easy plant to love
Despite its rarity, the American smoketree is easy to grow. It transplants easily and can establish quickly. In cultivation, the species has proved to be cold hardy in the north. It may have migrated toward the south during the ice ages, thus retaining its former cold-hardiness.
This tough tree is adaptable to a wide range of soils. It will grow in average pH soils with average to medium moisture levels. It will also thrive in poor, rocky soils, and even prefers well-drained, somewhat infertile loams. It is tough enough to tolerate long droughts, heat, and dry and gravelly soils. Ideally, the smoketree should be well-drained, and it prefers full sun. Young plants in sunny locations can grow rather rapidly, up to two feet a year.
You will surely fall in love with this unique tree. Its casual appearance in summer gives way to a marvelous display of scarlet, pumpkin-orange and purple in the autumn. Specimens in sunny locations generally have the best fall color, but genetic variations or soil characteristics may have an influence. For a touch of something unexpected and highly ornamental, this is a smart choice for an accent tree.
Just the facts
To know Cotinus obovatus is to love it. Take a moment to absorb this information and you'll be smitten.
A pop of American smoketree's fall color stands out in the landscape and signals the changing seasons.
Botanical name: Cotinus obovatus Raf. (= Cotinus americanus Nutt.)
Common names: American smoketree; smokebush; Chittamwood
Family: Anacardiaceae (the sumac or cashew family)
Zone: Cold hardy from Zone 4 to 8
Plant type: A deciduous, dioecious small tree or large shrub
Use: Massed or grouped in the shrub border; as specimen; on difficult sites; for mid- and late-summer flowering effect; a striking accent plant
Form: A large, multi-trunked shrub or tree with an upright or oval habit; width can equal height. Has a short trunk, open crown of spreading branches, resinous sap with a strong odor, and deep orange-yellow heartwood
Twig: Moderately stout, reddish green, glaucous, turning gray-brown with age; buds small, leaf scar lobed
Bark: Initially light gray-brown, later splitting into thin strips and becoming scaly and darker; attractive
Height: 20 to 30 feet
Spread: 20 to 30 feet
Leaves: Alternately arranged; simple, deciduous 2 inches to 5 inches long and half as wide; leaf margin entire, blunt-tipped; mostly obovate or oval leaf shape; bluish-green above, paler below
Outside the Bonsai Pavilion at the U.S. National Arboretum, a Cotinus obovatus-American smoketree-displays the characteristic wisps of "smoke" that give the plant its common name.
Summer foliage: Bluish-green leaf color with reddish mid-veins
Autumn foliage: Yellow, orange, red to purple fall color; showy
Flower: Large, open terminal panicles 6 inches to 10 inches long; small, greenish yellow to greenish white color occurring on many finely branched, slender clusters that resemble puffs of smoke; changes color from yellowish to pink as they age; few actual flowers occur that bloom early spring. The billowy hairs attached to elongated stalks on the spent flower clusters that from a distance suggest smoke gives the American smoketree its ornamental quality
Bloom time: May through June
Bloom color: Yellowish-green
Fruit: On female trees; drupe, small, with a single seed; light brown, 1/8-inch long, kidney-bean shaped; few appear on the slender branched, hairy pedicels. The fruit is small and not ornamentally important
Native: Southern United States; will grow in warm, temperate Northern Hemisphere; occurs in limestone glades, rocky limestone bluffs and bald knobs
Exposure: Full sun
Water requirement: Average or medium moisture; well-drained soil
Looks like: European smoketree
Propagation: By cuttings or by seed
Liabilities: Relatively trouble free; no serious insect or disease problems; occasionally gets verticillium wilt; has some susceptibility to leaf spots and rust
Barbara Bullock is a horticulturist at the U.S. National Arboretum and oversees the facility's extensive historical Azalea Collection. She can be reached at Barbara.Bullock@ars.usda.gov. (Mention of a trademark, proprietary product or vendor does not imply its approval to the exclusion of other products or vendors that may also be suitable.)