Submitted photo Caring for your hydrangeas can change depending on which species you have.

Pruning hydrangeas starts with knowing what type you have.

Danielle from Poland asks, “When should I prune my hydrangeas? I have two or three varieties and don’t know when they should be pruned.”

Danielle, the short answer is that hydrangeas should be pruned according to when they set their flower buds. Get the timing wrong, and you may remove this year’s blooms. Get it right, and you can keep the plants healthy, shapely and floriferous without a lot of fuss.

Most hydrangeas do not need heavy pruning every year. In many cases, the job is simply to remove dead wood, cut out winter damage and lightly shape the shrub. Pruning can also improve air circulation and help keep an older plant from becoming too dense, thus decreasing the chances of disease developing.

The key to hydrangea pruning: old wood or new wood. The most important thing to know is whether your hydrangea blooms on old wood or new wood. “Old wood” means stems that grew last year. “New wood” means growth produced in the current season.

Hydrangeas that bloom on old wood: These should be pruned soon after they finish flowering. This group includes bigleaf hydrangeas (H. macrophylla), mountain hydrangeas (H. serrata), oakleaf hydrangeas (H. quercifolia) and climbing hydrangeas (H. anomala). This group sets their buds in August or September. If you prune later, you risk cutting off the buds that would have produced flowers. Deadhead and remove any winter killed stems after spring growth appears.

Bigleaf and mountain hydrangeas shape or deadhead lightly after bloom. Rejuvenate older plants by removing up to a third of old older stems at the base of the plant.

Oakleaf hydrangeas usually need only light pruning, mainly to remove dead wood or improve shape after flowering.

Climbing hydrangeas usually need very little pruning beyond tidying or controlling size after flowering.

Hydrangeas that bloom on new wood: Smooth (H. arborescens) and panicle hydrangeas (H. paniculata) are much more forgiving. Because they flower on growth made in the current season, they can be pruned in late winter or very early spring before new growth begins.

Smooth hydrangeas can be cut back in late winter but cutting them extremely low can sometimes lead to weaker, floppier stems. Many gardeners leave a low framework of stems for better support and stronger flowering shoots.

Panicle hydrangeas can also be pruned in late winter or early spring to control size, remove weak stems and encourage strong new flowering shoots.

What about reblooming hydrangeas? Some newer bigleaf and mountain varieties are reblooming (remontant), meaning they can flower on both old and new wood.

These reblooming types are more flexible, but they still respond best to a light touch. Remove winter-killed stems in spring after new growth begins, and deadhead after the first flush of flowers if needed.

With hydrangeas, identification comes first — and once you know what type you are growing, the right pruning schedule becomes much easier to follow.

For an excellent, comprehensive factsheet on hydrangeas, visit: https://ohioline.osu.edu/factsheet/hyg-1263

Sprague is an Ohio State University Extension Master Gardener Volunteer in Mahoning County.