The purple smoke tree (Cotinus coggygria) sports tiny flower clusters that resemble smoke when viewed from far away. With glossy deep purple leaves and pinkish-purple flowers, the smoke tree adds color to a yard. This tree can be kept shrub-like with regular pruning or, if left untended, can reach 15 feet in height. Gardeners can choose from two pruning approaches that cater to a shrub-sized or tree-sized smoke tree. Prune the tree annually in late winter or early spring, once frost danger passes for your area.
Cut your purple smoke tree back every year in the early spring if you want to keep it shrub-like. Using anvil pruners, clip back each stem one at a time, leaving only two to three buds per stem. If you want your smoke tree to reach its maximum height of 15 feet, skip this step.
Identify dead, diseased or damaged branches on your smoke tree; these need to be removed for the health of the tree. Dead branches feel hollow and don't move in the wind. Diseased or damaged branches have discoloration, scarring or wounds and appear physically different from other growth.
Clip off dead and unhealthy branches on your smoke tree using anvil pruners. In between each cut, spray your pruners with a disinfectant spray to avoid spreading disease to healthy parts of the tree while pruning.
Prune off branches that crisscross other branches by cutting them off at the base or back to a Y-intersection.
Head back long branches one at a time with your anvil pruners. Clip them back to the desired height, cutting just above a leaf node or back to a lateral branch. This helps maintain the size of your smoke tree
Remove downward-growing branches or branches that impede movement underneath your smoke tree.