Answer: There is a good rule of thumb to follow when pruning shrubs. Shrubs that bloom in spring may be pruned immediately after flowering.
Shrubs that bloom after June (often the case with Rose of Sharon) usually do so from buds formed on shoots that grow the same spring. Such shrubs should be pruned in very late winter/very early spring to promote vigorous shoot growth later on in the spring.
Arborvitaes can be pruned in the spring, after new growth begins.
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