Lush hydrangeas full of pink, white, purple or blue blooms can make a big impact in nearly any landscaping plan. While you'll need to be careful of pruning hydrangea varieties which bloom on last year's wood, you can prune Annabelle, All Summer Beauty, Oakleaf, PeeGee and Endless Summer varieties in the winter without fear of cutting off necessary stems. After a good pruning, your hydrangeas should grow well for the next three to five years without needing any pruning.
Let the hydrangea sit until winter comes and the leaves fall off as the plant goes dormant. If you have plans to cover your hydrangea for the winter then you'll want to prune immediately following the first frost whether the leaves are off or not.
Select dead branches which weren't productive for flowering or leaves over the summer months. Cut off the dead branches as close to the ground as you can with a clean horizontal cut and carefully pull them away from the rest of the plant without breaking off other branches.
Look over the plant to make note of older, woodier branches. Clip the old branches down by a third to a half in length just above a set of leaves or at a branching point to help mask the cut and encourage growth.
Clip off any weak or misshapen new growth which appears droopy or diseased. As you clip these away, look over the plant for any branches which rub against one another or on structures the plant is planted near and clip them back as needed. Leave all other new growth undisturbed.