Prune apple trees, including flowering crabapples, mountain ash, hawthorns and shrub cotoneasters in late winter (February-early April). Spring or summer pruning increases the chances for infection and spread of the bacterial disease fireblight. Autumn or early winter pruning is more likely to result in drying and die-back at pruning sites. Prune summer-flowering shrubs in late winter or early spring. The pruned shrubs will bloom in summer on the current season's growth.
Some deciduous shrubs don't produce attractive flowers. These shrubs may possess colorful bark, fruit, or foliage. Prune these shrubs in late winter or early spring before growth begins. Do not prune deciduous shrubs in late summer. Pruning.