Cotinus is a very small family of garden shrubs consisting of just two species, commonly called smoke bush or smoketree. These shrubs are close relatives of sumacs and are members of the Anacardiaceae family. They are native to the southeastern part of the United States, as well as parts of Eurasia. This deciduous shrub gets its common names from its flowers, which are very unusual, with clusters of tiny fluffy blossoms that resemble puffs of smoke.
These shrubs or small trees are popular landscape accents, adding interest to yards and garden areas with their odd-looking flowers and bronze, bluish or purple leaves. In fall, the foliage turns a variety of bright colors, making them even more attractive to gardeners. They usually grow to no more than 15 feet tall (about 4.6 m) which makes them a manageable size for even small yards. The flowers bloom for quite a while, as long as two months from late spring to midsummer.
American smoketree, like all varieties of these garden shrubs, grows best in fertile soil. These shrubs will live in many different growing conditions, however, including packed clay soil, where not many plants grow well. Cotinus can also live in very hot climates and will tolerate drought and dry soil. They should not be grown in very wet soil, because they tend to develop root rot. While they prefer full sun, they will tolerate some afternoon shade, though their foliage will not be as colorful.
To keep cotinus plants looking their best, they should be pruned back to the ground after frost, or in early winter in warmer areas. This severe pruning will increase the number of flower clusters, because this shrub blooms on new growth. Pruning will also encourage brighter foliage the following spring.
Cotinus shrubs are either male or female, and one of each is needed for them to produce seeds. The seeds are slow to germinate and should be planted in the ground in fall to produce seedlings in the spring. The seeds store well and will remain viable for several years if stored in a dry, airtight container. Cuttings can be difficult to root, though dipping them in rooting hormone powder may be helpful. Small cuttings should be taken in summer or fall and kept indoors until they can be planted the following spring.
Cotinus is susceptible to some plant diseases, including verticillium wilt, powdery mildew and leaf spot. Harmful insects stay away from them, though bees and butterflies are frequent visitors. They are a good choice for gardens in areas heavily populated by deer, which usually don't bother with these plants.