You should have pruned rose of Sharon in late fall or winter after leaves drop in your flower gardening. You can prune in early spring before buds form. If pruning done later than early spring may cause the loss of some blooms. Remove any branches that appear dead or damaged from storm or winter damage. Also remove branches that appear to be growing in wrong direction.

Also remember to remove any suckers sprouting from the bottom of the trunk, growing from the roots or sprouting nearby growing area. Thin out branches which block sunlight or prevent air circulation through the plant. Remove the weak branches down and only prune back healthy branches to the node which allow the desired appearance.