When Is the Best Time to Prune Hydrangeas?

1. Understanding Hydrangea Types and Their Pruning Needs

Hydrangeas are diverse, and their pruning requirements depend on the species. The two main categories are:

• Hydrangeas that bloom on old wood (previous year's growth): These include Hydrangea macrophylla (bigleaf), H. quercifolia (oakleaf), and H. serrata (mountain hydrangea). Pruning at the wrong time can remove next season's flower buds.
• Hydrangeas that bloom on new wood (current season's growth): These include Hydrangea paniculata (panicle) and H. arborescens (smooth hydrangea). These are more forgiving and can be pruned in late winter or early spring.

2. Best Time to Prune Old-Wood Bloomers

For hydrangeas that flower on old wood, timing is critical to avoid cutting off future blooms. The ideal window is immediately after flowering, typically in late summer or early fall. This allows the plant to develop new buds for the next year before winter dormancy. Pruning later (e.g., winter or spring) risks removing these buds, resulting in fewer or no flowers.

3. Best Time to Prune New-Wood Bloomers

Hydrangeas that bloom on new wood benefit from pruning in late winter or early spring, just before new growth begins. This timing encourages vigorous growth and abundant flowering in the upcoming season. Since these varieties produce flowers on current-year growth, pruning earlier (e.g., fall) is unnecessary and may expose the plant to winter damage.

4. Special Considerations for Reblooming Varieties

Some modern cultivars, like Endless Summer or BloomStruck, bloom on both old and new wood. For these, light pruning after the first flush of flowers in early summer can promote a second bloom. Avoid heavy pruning in fall or winter, as it may reduce spring flowering.

5. General Pruning Guidelines for All Hydrangeas

Regardless of type, follow these principles:

• Remove dead or damaged wood: This can be done anytime, even in winter.
• Avoid over-pruning: Hydrangeas rarely need drastic cuts. Focus on shaping and thinning rather than reducing size.
• Use clean, sharp tools: Prevents disease and ensures smooth cuts.

6. Climate and Regional Adjustments

In colder climates, protect old-wood bloomers by delaying pruning until spring to identify winter-killed stems. In warmer regions, pruning timelines may shift slightly, but the same principles apply.