Pruning Oakleaf hydrangeas is best done in the early spring and should be done with care. New growth can be removed or inhibited when pruning is done incorrectly.
Oakleaf hydrangeas do not require pruning for survival. Pruning is done to reduce overgrowth and increase the aesthetic value of the bush. Stems that have grown during the current season but have not bloomed should not be pruned, as this discourages the growth of new stems and flower buds.
Remove dead branches and flower heads when necessary. Pruning dead stems and older wood on the bush serves to revitalize the plant. Old wood and stems can be cut all the way down to the ground, as oakleaf hydrangeas have a fast growth cycle and will return to their normal size in a timely manner.