When it comes to pruning hydrangeas, timing really is everything. The trouble comes with determining the best time. It depends on the type of the hydrangea and what type of pruning it needs to look its best and remain healthy.

Summer Pruning

Hydrangeas that are in the macrophylla group—which includes mopheads, lacecaps and oakleaf hydrangeas—flower on old wood. These require pruning in summer, preferably before August, so the new buds that will flower next year aren't removed. Winter and spring pruning trims off the buds, so you end up with plenty of foliage but little to no flowers.

If your hydrangea is still in flower in July, you have two options. You can skip the annual pruning, or you can go ahead and prune it. Skipping the trim is only a good idea if the hydrangea is in good health and doesn't really need pruned. If you decide to prune it anyway, you will lose some flowers but it will return to full bloom next year.

Summer, Fall and Winter Pruning

The second group of hydrangeas flowers on new wood. These include the paniculata and arborescens groups, which encompasses PeeGee and Annabelle varieties. These hydrangeas don't form flower buds until the spring, so you can have them pruned at any time after flowering up until late winter.

New wood blooming varieties can tolerate heavy pruning. You can often cut back the entire hydrangea to the ground and it will regrow from the stump. This is one way you can rejuvenate the hydrangea if it becomes overgrown or weak.

Pruning Basics

All hydrangeas require the same basic pruning steps, regardless of the season they need pruned.

  1. Cut out any dead or weak stems. Make the cut at the base of the stem.
  2. Prune back overgrown branches to the desired length. Make the cut near a leaf so bare stem tips don't show.
  3. Every five years, trim down the oldest stems to the ground to revitalize the hydrangeas and provide better air circulation.

PeeGee hydrangeas can also be trained to a tree form. To do this, only trim out dead wood from the top third of the tree, and then remove any lower branches that form when you do your usual annual pruning.

Although not necessary, you can remove the dead blossoms from your hydrangeas at any time of year. This makes the shrub look better and it may help increase flowering for next year. If you find a dead or diseased branch, go ahead and trim it out without worrying about the season. For more information, contact a tree pruning service like Woodland Tree Expert CO.