When to prune hydrangeas

Depends on the type: old-wood bloomers right after flowering, new-wood bloomers in late winter. Hydrangeas. Type your town for the dates at your weather station.

It depends on the type

Bigleaf and mountain (flowers on old wood)

When: Right after the flowers fade in summer; only remove dead stems in spring.

• Flower buds for next year form on the stems in late summer and fall, so fall, winter or spring cuts remove them and you may get few or no flowers.
• Take off no more than about a third of the plant when shaping.
• Reblooming cultivars flower on old and new wood; prune lightly right after the first flush.

Panicle and smooth (flowers on new wood)

When: Late winter or very early spring, before new growth starts.

• Flowers form on stems that grow the same season, so a late winter cut does not cost you blooms.
• Smooth hydrangea can be cut back hard, close to the ground, and regrows quickly.
• Panicle hydrangea is a larger woody shrub; cutting it lower or thinning stems gives fewer but bigger flower heads.

Oakleaf (flowers on old wood)

When: Soon after flowering in early summer, if at all.

• Oakleaf hydrangea blooms in summer but sets its buds the year before, so it is an exception to the 'summer bloomers in late winter' rule.
• It usually needs little pruning; cut only to manage size and shape.

Climbing (flowers on old wood)

When: After the flowers fade.

• Climbing hydrangea needs only light shaping.
• Like other old-wood types, cutting it in winter or spring removes that year's flowers.

How to prune hydrangeas

• Identify the species first. Timing depends on whether it blooms on last year's stems or this year's stems.
• Dead, damaged or broken stems can be removed at any time.
• Cut back to a healthy pair of buds or a side branch, not to a bare stub.
• Smooth hydrangea stems can be cut to within a few inches of the ground (about 2 to 4 inches) in early spring, before new shoots appear.
• Panicle hydrangeas left unpruned for years carry their flowers higher and higher; cutting last year's stems back each spring keeps blooms at a viewable height.
• To deadhead, cut the spent flower stem back to the first pair of plump, healthy buds or a side branch.
• Old flower heads can be left on through winter and removed in spring; they do not harm the plant.
• New-wood types (panicle and smooth) tolerate removing about a third to a half of the plant in late winter without losing that summer's flowers.

What to avoid

• Do not cut bigleaf, mountain, oakleaf or climbing hydrangeas in fall, winter or spring; that removes the buds for the next bloom.
• Avoid heavy pruning on old-wood types; it reduces the next season's flowers.

Pruning window by zone

Counted from the typical last frost of each zone (the middle value among its towns of 10,000 people or more). Buds swell earlier in a warm spring, so watch the plant as well as the calendar.