The purple smoke bush is a cultivar of the traditional smoke tree. The leaves are a maroon red that eventually matures to dark purple then transitions to scarlet red in the autumn months. Pruning time for these bushes depends on whether you want a shrub or a tree.
Purple smoke bushes need pruning each year in the early spring if you want to keep them shrublike. If you are aiming for a small tree, prune only in late winter or very early spring, cutting very little.
What to Prune
If the aim is for a shrub, prune to near ground level for the first two years to encourage the bush to form multiple stems. This generally payoffs with a much fuller shrub in the end. If you want a tree, choose the main trunk and prune around it to form the tree's shape.
Purple smoke bushes require full sun to bring out the best colour out of the leaves and they prefer well-drained, but moist soil. They will grow in moister areas but are more prone to root rot in such instances.