Pruning Oak Leaf Hydrangea;
In OK, when is the best time to prune an oak leaf hydrangea that has been somewhat disfigured by a bout of black spot?
Certified GKH Gardening Expert
Oakleaf hydrangeas bloom on old wood, which means the buds formed the season before they bloom. So any pruning should be done in summer after bloom. However, prune out dead or diseased parts as soon as they are noticed. You may have to sacrifice some blooms.