During her 2014 New York ReLeaf Conference plenary talk, Urban Horticulture Institute Director Nina Bassuk lifted up some underutilized trees for urban use. One of them, American smoketree (Cotinus obovatus) was growing just outside the conference room doors on the Hofstra University campus, where a mature specimen stood protectively behind a newly planted youngster. American smoketree is native to the U.S. South and Midwest.
Naturally and by training, American smoketree has a more tree-like habit than European smoketree (C. coggygria), and it matures up to 30 feet (9 m) tall and 20-30 feet (6 to 9 m) wide—twice as big as C. coggygria. It is hardy to zone 4 or 5, depending on which reference you consult. It is deer resistant and tolerant of drought and poor soils but doesn’t like to have wet feet for prolonged periods. Missouri Botanical Garden voted it one of its “Tried and Trouble-Free” tree species.
The flower panicles* are not quite as showy as those of European smoketree, but American smoketree’s fall color can be really spectacular, with some combination of yellow, red, orange, and purple. The Missouri Botanical Garden Plant Finder site says it “produces some of the best fall color of any of the native American trees and shrubs.” Best fall color is achieved in full sun. (*The showy “smoky” effect is from the hairs that emanate from flower stems after the flowers themselves are gone.)
When I was doing my landscaping business in Rochester, NY, I liked to use ‘Grace’ for my clients (and was lucky enough to have a nearby plantsman keeping it in stock). ‘Grace’ is a hybrid of the native and European smoketrees, with the best features of each, including lack of significant disease or insect problems. It only achieves the height of its European parent, C. coggygria.
On the Cornell Woody Plants database site (http://woodyplants.cals.cornell.edu), Nina Bassuk writes of Cotinus obovatus, “This species has almost no cultivars and any that exist are rare (hard to find). It has a lot of potential, particularly for creating cultivars with superior fall color, improved urban hardiness; improved form; and superior panicle color/yield. Keep an eye out for new varieties in the future.” —Michelle Sutton, TAKING ROOT Editor