Cotinus, or the smokebush or smoketree (Cotinus coggygria), is a deciduous shrub revered for its rounded foliage and fine, smoke-like powdery puffs of tiny flowers in late spring. Pruning this shrub can be either for general shaping of its natural form, or coppicing, which is a more intensive and severe pruning approach. Coppicing is done annually each early spring and causes the plant to send up many watersprouts, or fast-growing stems with intensely colored foliage, which are amazingly ornamental.
Casual Pruning Technique
Scan over the shrub, looking for any dead or damaged branches. Remove these branches with a crisp, one-motion snip of the hand pruner blades one-quarter inch above a live branch junction or a leaf or dormant bud. Use loppers on branches that are larger than one-half inch in diameter.
Plan to prune the shrub in early spring if you wish to shape it without removing existing flower or foliage. Early March is an opportune time, when the weather is mild and the smokebush has not yet sent out its new leaves.
Reduce branches to the desired length on the shrub to make a more rounded, even or pleasantly-shaped plant. Always make pruning cuts one-quarter inch above a dormant bud on an alive branch. Living twigs are pliable and somewhat soft and easy to bend gently when no leaves are obviously present.
Tip prune new growth occasionally as needed during the growing season, but no later than late summer. Pruning done when leaves are present causes temporary bald spots and the loss of the attractive foliage.
Cut back all stems and main branches of the shrub in early spring before any leaf buds swell and break. Hand pruners can cut branches less than one-half inch in diameter, but loppers may be needed on thicker branches.
Make the pruning cut one-fifth to one-half inch above the joint between the branch and the main trunk of the shrub. This usually means the plant is reduced a collection of stubs above the one trunk stem at a height of 6 to 12 inches.
Allow the mass of leggy sprouts to grow from the severely cut-back shrub. Do not further prune them but permit them to reach skyward and become long and display the intensely colored foliage. These watersprout stems will not flower.
Repeat Steps 1 through 3 the following early spring to continually coppice and renew the growth of the intensely colored foliage and branches. After three years of coppicing, there will be a significant mass of cut-back stumps at the base of the shrub. Do not worry of removing any part of the mass unless parts are rotted or dead.