How to prune hydrangeas

Pruning hydrangeas can be a bit tricky. The key is knowing which type you have. Why? Because some hydrangeas flower on new wood (stems that form in the current season) and some on old wood (stems that formed last season). If you prune at the wrong time, you could be removing the plant’s ability to bloom next season.

Prune mophead, lacecap, and oakleaf varieties in mid-summer because they bloom on old wood. These varieties bloom in the early spring on wood that formed during the previous growing season. Pruning is best performed in mid-summer after the peak of the bloom. This timing is important, because it allows the plant to devote the remainder of the growing season to the development of the buds that will become next year’s flowers. Here’s how to prune hydrangeas that bloom on old wood.

Photo: KENPEI, Creative Commons

Prune panicle and smooth varieties in winter, because they bloom on new wood - that is, wood that forms during the current growing season. These varieties often bloom well into fall and are vigorous, upright, fast-growing plants. Removing spent blooms at the base can keep a plant looking tidy without sacrificing wood on which flowers form. Here’s how to prune hydrangeas that bloom on new wood.