Cotinus obovatus, commonly called the American Smoketree, is native to Northern America. Other common names include Chittamwood and American smokewood.
Cotinus obovatus belongs to the genus Cotinus in the Anacardiaceae Family, and it is a rare flowering plant for the genus.
The American Smoketree gets the name from the clusters of its tiny blossoms, which look like the puffs of smoking from a distance.
The tree could grow up to 20 to 30 ft (7 to 10 m) tall. They are best planted as an accent plant or en masse in a shrub border.
In the spring, the leaves look bronze to purple, whereas in the summer they are are bright green.
When it comes to the fall color, the American Smoketree is among the finest native trees in the Americas.
The brilliant fall colors range from yellow through to deep red, indeed the Smoketree becomes spectacular in autumn.
Many colors can occur on a one single tree. Specimens grown in sunny locations usually have the best color.
The conjunction of the smokey look of the spring flowers and the spectacular fall color together make the American Smoketree an highly ornamental plant to grow in your garden.
Plants are known to be tolerant of deer, rabbits, drought, and can even grow fairly well in clay soils.
Gardener's HQ Guide to Growing Cotinus obovatus
Light
Cotinus obovatus should be planted in the full sun.
Soil
Cotinus obovatus trees do well in almost any kind of soil as well as almost any level of PH.
A slightly sandy soil is ideal, but other types are fine too. Good drainage is required as the only soil condition that cannot be tolerated is damp and soggy soils.
Watering
When established, the Smoketree has very good tolerance for dry conditions. However, when becoming established, the tree requires to be regular watered.
Temperature and Humidity
The Smoketree does best in moderate temperatures and in average to dry humidity levels.
In more moist and warm climates, fungal diseases may occur.
Fertilizer
The Smoketree does not need much feeding. Maybe fertilize the tree every spring through adding a layer of compost.
Propagation
Propagation is generally by cuttings and seedings. The seeds need to be soaked initially in water for 24 hours and dried, then planted at around 1/2-inch-deep (1.2 cm) in a sandy soil.
That said, germination can be very difficult and seeds may need to undergo a double stratification process.
Transplanting
Cotinus obovatus is easy to transplant as it has a contained fibrous root system. It is best to transplant in the spring, ensure that the plant has a good rootball.
When transplanting, dig down to a depth of 12 to 14 inches (30 to 35 cm) around the tree and carefully lever the ball of root out of the ground. Next, move the ball of the root to its new location.
Growing and Care Guide
Scientific Name: Cotinus obovatus. Syn. C. americanus, C. cotinoides, and Rhus cotinoides.
Common Name (s): American Smoketree, American smokewood, Chittamwood.
Growing Zone (USA / UK Hardiness): USDA Zones 4 to 8. The equivalent UK growing zone to USDA 4 is colder than the lowest RHS zone (H7).
Best used for: Landscaping. Autumn leaf fall color. Shrub borders. Accent plant.
Plant Details
Life Cycle / Plant Type: Deciduous flowering tree. Shrub-like.
Plant Height: 15 to 50 feet (5 to 15 m).
Plant Spread: 15 to 30 feet (5 to 10 m).
Blooms: Summer. Dioecious.
Flower Details: White but inconspicuous. Hairs appear on spent flower stalk clusters. These have a fluffy smoky pink appearance.
Leaf Foliage: obovate, inverted egg shape. Blue-green leaves turn a striking scarlet red in the autumn. Foliage can also turn yellow, orange, or purple.
Fruit: Fruits appear in clusters in the summer. Brown. Oblong. 5 mm (1/5th inch).
Growing Conditions and Location
Best Light Conditions: Full sun or partial shade.
Suitable Soil Types: Although it performs well in sandy and normal soils it seems to be fine in poor soils too. It is naturally found in mountain soils.
Soil Moisture: Medium.
Sowing, planting, and Propagation: Germination can be difficult.
Pre-soaking seeds may work, but if then subject to a warm stratification for two months followed by four months of cold stratification before sowing.
Care: Pretty much looks after itself once established, keep soil fairly moist during initial growth. Prune to help develop strength.
Growing in pots and containers: No.
Cultivars:
Red leaf: grown for its autumn red color)
Grace: this is a cross with Cotinus coggygria (European smoketree), it tends to be taller than normal and has reddish-purple leaves that intensify into a wonderful scarlet in the autumn.
Further Information
Miscellaneous: Resistant to cold, heat, and drought. Fairly resistant to deer. Genus named after its closeness to olives (see my Olea europaea growing guide). Bright yellow Heartwood. Attractive Bark.
Further Reading and References: Missouri Botanical Garden; OSU Landscape plants.
Family: Anacardiaceae (Cashews / Sumac).
Gardener's Questions
What is Cotinus obovatus?
It is a deciduous tree native to mountain areas of southern USA.
How tall are Cotinus obovatus?
Plants generally range from 5 to 10 m (15 to 30 feet) in height, and have similar spreads. Some trees have been reported to reach 15 m (50 feet) in their native habitat.
How to Germinate Smoketree Seeds?
Use seeds within two years. Sow plenty as most seed will be infertile.
Collect whole panicles in early spring. Air dry seeds and remove panicles. Moist stratify seeds in a warm area for a couple of months, followed by a few months at fridge temperature.
If seeds do not germinate then consider treating them for 30 minutes in sulfuric acid to scarify them.
How do I prune Cotinus obovatus?
Pruning should be done outside of the growth period in late summer or early autumn.
If you prune outside this period then bleeding is very likely to occur.
I hope that you enjoyed this garden plant guide on how to grow Cotinus obovatus. You may also enjoy the following cashew family plant growing guides: How to grow Smooth Sumac and Pistacia chinensis plants.
