How to prune mountain hydrangea 'bluebird'

Immediately after flowering (late summer), or dead-flower tidy-up in early spring (March–April). Cut spent flower stems back to the first healthy bud pair. In early spring, remove any winter-killed tips down to live wood. Every few years, remove one-third of the oldest stems at the base to rejuvenate.

Annually (lightly). Light touch only — Bluebird blooms on old wood just like bigleaf hydrangeas. Prune immediately after flowering finishes in late summer. Avoid pruning in autumn, winter, or spring, which removes developing buds. The plant benefits from having spent flowerheads left on over winter for frost protection, then tidied in early spring.

Cut spent flower stems back to the first healthy bud pair. In early spring, remove any winter-killed tips down to live wood. Every few years, remove one-third of the oldest stems at the base to rejuvenate.