Answer: This type of hydrangea blooms on old wood that grew the year before, so you need to be somewhat cautious about pruning it. You can selectively remove the longest stems. This will thin it a bit and help keep the center of the plant open to air and light and will also keep it a bit shorter. The best time to do this is right after it blooms, or else in early spring. If you prune in the spring however you will reduce flowering this summer. You may also find that the occasional severe winter prunes the bush back hard for you by killing off part or most of the stems and thus reducing the overall size.
Q&A Library Searching Tips