I am frequently asked at this time of the year about pruning hydrangeas. The last few garden coaching clients I have seen mentioned that their mophead hydrangeas (Hydrangea macrophylla) simply don’t bloom well for them. When I hear this, the first thing I ask is when they typically prune them. Often, the answer is ‘now’.
If you’ve had your mophead hydrangea, also called bigleaf hydrangea, for more than a few years, chances are pretty good is the type that blooms exclusively on old wood. That means it sets it buds for THIS summer’s flowers on shoots that developed after the plant bloomed LAST summer. So proper timing of pruning is a must for successful flowering.
Since hydrangeas are such popular garden shrubs, there are several new cultivars of hydrangea macrophylla that are re-blooming, meaning they bloom on old wood and new wood. The most popular re-blooming hydrangea is arguably Endless Summer. If you have a re-blooming hydrangea the timing of pruning is not such an issue.
What many gardeners don’t realize is that bigleaf hydrangeas do not really have to be pruned back unless they are very old and need rejuvenating. Removing dead stems is the only pruning that should be done to keep the plant healthy and they can be removed at any time of the year. If you want to revitalize an old bigleaf hydrangea that isn’t flowering well, you can cut about one-third of the oldest shoots back to ground level each summer.
At this time of the year in cold-climate gardens like mine here in southwestern Connecticut (zone 6), it’s time to deadhead any old, faded flowers that were left on the hydrangea for winter interest. Be careful how you deadhead so you don’t accidentally prune off this summer’s flowers. While I could tell you how to deadhead, it’s much more effective to see how it’s actually done. For a look at the proper technique on deadheading mophead hydrangeas, click here to see a video tutorial by Genevieve Schmidt of North Coast Gardening in CA. Even though Gen is located in northern CA, the technique she demonstrates is relevant no matter which zone you garden in.
With proper care and pruning, you can have big beautiful hydrangea flowers all summer long.
Debbie, what a clear explanation for people. I so appreciate how you manage to be thorough without being confusing. Thanks for the link to my video. Between the two of us we’ll have folks pruning hydrangeas like champs (and still getting blooms!!).
Hi Debbie, Interesting post. A bit farther north, we may not get any blooms on the mopheads even if we don’t prune due to winter kill. It’s a bit misleading that they’re listed as hardy here in zone 5- the plant won’t die, but you may not get reliable bloom. Hope you’re enjoying the glorious weather today! Cyndy
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