AMERICAN SMOKE TREE, COTINUS OBOVATUS A distinctive and underused specimen tree
Sarah Roberts, Director of Historic Gardens and Living Collections Atlanta History Center, Atlanta, Georgia
Many small ornamental trees grace our Atlanta neighborhoods with spring or summer flowers but few have such handsome foliage and brilliant fall color as our American smoketree. The common name refers to the cloud-like panicles of tiny flowers with showy stems that create a dusky pink haze in early summer.
The ever changing foliage emerges a soft bronzy-pink in spring. As the leaves mature, they become crisp and rounded with blue tones overlaying a dark green base, a perfect foil for the smoky plumage. Autumn brings the final transition into vibrant, flaming shades of orange and red that last up to four weeks. These colors are always best when it is grown in full sun.
When left untouched the American Smoketree (USDA Zones 5-8) will grow into a large shrub, but it can be easily trained as a small tree. Its short trunk (or multiple trunks) will open to a rounded, open crown of artistically twisted branches, ultimately reaching 20-30’ in height and width. The dark flaking bark of a mature specimen is especially noticeable in winter when the tree’s unusual silhouette is best appreciated.
Cotinus obovatus is not common in the nursery trade or in the wild. It is only found in isolated populations in the Southeastern US, though it is perfectly cold hardy to zone 5. Theories suggest that it was once native further north but was pushed south by the glaciers, and has retained its cold hardy nature. The species may be in danger of extinction in the wild due to the large trees being harvested for the yellow and orange dye found in their wood.
Though it is found in alkaline, dry, rocky soils in its native stands, the American smoketree is highly adaptable and will also thrive in neutral or slightly acidic average garden soil. It is disease resistant and drought tolerant so does not need much supplemental watering after establishment. A quick grower, it can achieve two feet of annual growth in its early years. It is excellent planted as a small specimen tree in front or back yards, as an urban street or parking lot tree since it is tolerant of pollution, drought and compacted soils, or as part of a mixed shrub border. Full sun brings the best flowering and foliage coloration, but it will grow admirably in partial shade as well.
Another variety of smoketree that is more common in the nursery trade is the European and Asian species, Cotinus coggygria. There are many selections based on foliage color and degree of floral smokiness, but all of them make better large shrubs than trees.All smoketrees are members of the Anacardiaceae family, a diverse group that includes cashew, mango, sumac and poison ivy.
Come see a mature specimen of Cotinus obovatus in the Mary Howard Gilbert Memorial Quarry Garden of the Atlanta History Center. It is a 3-acre native plant garden that features plants native to Georgia.
In conjunction with National Public Gardens Day, the Atlanta History Center offers free access to the Mary Howard Gilbert Memorial Quarry Garden, the other five gardens located within the twenty-two acre campus, and the new traveling exhibition, Following in the Bartrams’ Footstep: Contemporary Botanical Artists Explore the Bartrams’ Botanical Legacy. On May 9th visitors to the Atlanta History Center can also take complimentary guided tours of the gardens as well as the Following in the Bartrams’ Footsteps exhibition to learn more about the Bartrams’ travels and discoveries in colonial Southeastern America.
Tours indoors delve into the details of the supplies used during the Bartrams’ exploration and the writings they produced to document their findings. The garden tours provide a new understanding of how the plants featured in the exhibition have been used in the past, their ornamental features, and how visitors can grow the plants at home.
Atlanta History Center, 130 West Paces Ferry Rd NW, Atlanta, GA 30305, (404) 814-4000. Hours: Monday – Saturday 10:00 AM - 5:30 PM. Sunday Noon - 5:30 PM.
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By Dan Heims, President, Terra Nova Nurseries, Inc.
Photographs courtesy of Terra Nova Nurseries, Inc.
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Many small ornamental trees grace our Atlanta neighborhoods with spring or summer flowers but few have such handsome foliage and brilliant fall color as our American smoketree. The common name refers to the cloud-like panicles of tiny flowers with showy stems that create a dusky pink haze in early summer. 
