The timing for pruning hydrangeas depends on the type of hydrangea and whether it blooms on old wood, new wood, or both.

• Hydrangeas that bloom on old wood (such as bigleaf hydrangeas and oakleaf hydrangeas) should be pruned just after their flowers fade, typically in summer. Pruning them later in fall, winter, or early spring can remove flower buds and reduce blooming in the next season.

• Hydrangeas that bloom on new wood (such as smooth hydrangeas and panicle hydrangeas) should be pruned in late winter or early spring before new growth starts. They can even be cut back quite hard, especially smooth hydrangeas.

• Remontant or reblooming hydrangeas, which bloom on both old and new wood, can be pruned either in early spring or after the first flowers fade. Early spring pruning delays flowering, and pruning after the first flush of flowers may shorten the rebloom period.

• Climbing hydrangeas are typically pruned after flowering in late summer, to avoid cutting off buds for the next year.

Overall, pruning is best done:

• For old wood bloomers: right after flowering fades in summer.
• For new wood bloomers: late winter or early spring.
• For remontant types: early spring or after first flowers fade.
• For climbing hydrangeas: after flowering in late summer.

Leaving dried flower heads over winter can protect buds from frost damage in many types that bloom on old wood.

This timing approach ensures healthy growth and maximizes blooming for each hydrangea type.