Many people get confused about when to prune hydrangeas. It is essential to know which species or cultivar you have to determine when to prune.
Bigleaf hydrangeas (Hydrangea macrophylla) set flower buds on old wood, which develop in late summer and fall; therefore, pruning should be done immediately after flowering. Be sure to remove only a third of the total growth of the plant. The cultivars in the Endless Summer® series are an exception to this rule. The first flush of flowers of these cultivars usually bloom on old wood; therefore, any necessary pruning should be done immediately after blooming. Flower buds will then form on new wood, and the Endless Summer® hydrangeas will repeat bloom throughout the summer.
Bigleaf hydrangeas (Hydrangea macrophylla) develop flower buds on old wood.
Barbara H. Smith, ©2019 HGIC, Clemson Extension
The Endless Summer® series of bigleaf hydrangeas develops flowers buds on old and new wood.
Barbara H. Smith, ©2019 HGIC, Clemson Extension
The panicle (Hydrangea paniculata) and smooth hydrangeas (Hydrangea arborescens) develop flowers on new wood produced during the current growing season. Since they develop flowers on new growth, they can be pruned either in late winter or early spring while the plants are dormant and before new growth begins.
Panicle hydrangeas (Hydrangea paniculata) develop flower buds on new wood.
Barbara H. Smith, ©2019 HGIC, Clemson Extension
Smooth hydrangeas (Hydrangea arborescens) bloom on new wood; therefore, should be pruned just before new growth emerges in the spring.
Barbara H. Smith, ©2019 HGIC, Clemson Extension
Oakleaf hydrangeas (Hydrangea quercifolia) bloom on old wood. They should be pruned soon after flowering to maintain a desired height and shape.
Barbara H. Smith, ©2019 HGIC, Clemson Extension
Oakleaf hydrangeas (Hydrangea quercifolia) flowers develop on old wood from last year’s growth. It blooms in June; therefore, to maintain a desired size and shape, they should be pruned soon after flowering. This will allow these beautiful native hydrangeas time to develop flower buds for the following year.
For more detailed information on pruning and hydrangeas, see HGIC 1067, Hydrangea, and HGIC 1053, Pruning Shrubs.
