One of the most common questions I am asked is, “when is the best time to prune my hydrangeas”? My answer is– it depends.
It takes a bit of work on your end to pay attention to your plants and watch when they bloom –and whether they bloom on ‘old wood’ (the stems from the previous year) or new wood (new growth from bottom of the plant). So, if you don’t know for sure that your plant blooms exclusively on NEW wood, DON’T cut them back until you know.
Patience is a virtue here– just wait. Sometimes the branches that truly look dead will surprise you from producing buds–often starting at the bottom of the branch. And some hydrangeas now bloom on both old AND new wood– as if we weren’t confused enough already! 😉
Click on this link from fine gardening magazine for more info.