Answer: Prune your tree form Rose of Sharon in late winter or early spring. If you have a few errant and overly long branches now, you can prune them back anytime during the summer months, but save the major pruning for late winter or early spring. Reducing the size by about one-third would be considered hard pruning and will result in fewer but larger flowers; light pruning, or no pruning at all will result in lots of smaller flowers.
Best wishes with your Rose of Sharon.
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