Sign up for our newsletter
Gardening in the Rainy Zone.
Cotinus coggygria 'Royal Purple'
SMOKE TREE, SMOKE BUSH
Pronounced: koe-TY-nus koe-GIG-ree-ah
Sunset zones: 2-24.
USDA zones: 5-9.
Heat zones: 9-3.
Height: 15 feet (5 m).
Width: 15 feet (5 m).
Late spring to early summer.
Panicles of small, insignificant flowers that give the shrub a smoke-like appearance.
Oval, dark purple foliage with red veins and stems. Leaf margins are edged with a thin line of red. Leaves turn scarlet in autumn.
Full sun to partial shade. Purple color is best in full sun.
Moist, fertile, well-drained soil.
Side dress with compost in fall.
Root softwood cuttings in June for best results.
To keep the plant shrub-like, cut all stems back to within 2-3 buds from the base, annually, in early spring. For growing as a tree, in late winter to early spring, remove only crossing or wayward stems to maintain a healthy frame.
Pests and Diseases:
Verticillium wilt may be a problem. Powdery mildew may be a problem on purple-leaf forms.
Rainy Side Notes
Cotinus gets its common names, smoke bush or smoke tree, from its panicles of spent flowers that appear like puffs of smoke around the plant. It is easy to see why Great Plant Picks chose this shrub for their 2005 list. As summer draws near, the leaves turn purple, almost black, a nice contrast to the red veins and edging of the leaf margins.
C. 'Royal Purple' has leaves which change color throughout the seasons, starting out in spring sporting its new fresh attire of maroon-red. In fall, its fashion statement appears in shades of scarlet. However, in order to insure you get the most intense color display, select your tree when it turns color in autumn. Keep watering and fertilizing to a minimum, for best fall color.
When used with tin and alum mordants, the smoke tree's wood and bark chips give a clear yellow dye that's been in use since the Middle Ages. Using different mordants gives more hues, such as pink and an orange-tan. When mixed with indigo, the dye becomes a beautiful green.
Coppice the shrub for vigorous shoot growth and larger leaves. You will sacrifice the flowers with this practice, so you will have to decide if you want it to smoke, or sport wonderful leaves. This is one time where "to smoke" is politically correct in the Pacific Northwest, although the tree still has to smoke outdoors. If left as a tree, practice only minimal pruning, or you will wind up with leggy, unsightly branches. I am growing mine into a tree form, as its optimum height will stay this side of shy of power lines, which it grows beneath. Smokin'!
Top images photographed in author's garden. Bottom right image photographed in Joyce Hawkins's garden.