Bigleaf Hydrangea

Care guide

Provide afternoon shade. The combination of high elevation, late freezes extending into April, and intense sun following cold nights increases the risk of bud and tissue damage. Macrophylla buds are specifically vulnerable to this pattern.

Reblooming series (Endless Summer, Blue Enchantress) flower on both old and new wood, not old wood alone — which changes the practice considerably from the classic macrophylla advice.

Deadhead through the growing season for a second flush. Cut only the spent flower head back to the first strong pair of buds or leaves. Keep it shallow — the point is to trigger a reflush, not to shape the shrub.

Remove dead wood in spring, after leaf-out, once it is clear what actually survived the winter. No hard or deep cuts from fall through early spring. The early-season flush still comes from buds formed the previous season on existing stems, so heavy pruning costs that first bloom even though the plant will rebloom later on new growth.

Leave the final fall flush's spent heads on over winter — they insulate the old-wood buds against cold. Tidy them in early spring.

Early-to-mid March. Preserve a large root ball. Site in a location with afternoon shade. Be prepared to protect buds if late freezes occur after transplanting.

Late freeze bud damage: Hard freezes in March-April can kill the already-formed, exposed old-wood flower buds and tender new tissue. Macrophylla is more exposed to this than paniculata. On reblooming series, a bud-kill costs the early old-wood flush but not the season — they still flower on new wood later. Worth protecting for the earlier bloom, but not a season-ending event.

Early-mid March: Transplant if needed (large root ball, afternoon shade location). April: Protect buds if late freezes are forecast (cover or burlap) — saves the early flush. Spring, after leaf-out: Remove dead wood only. Through the growing season: Deadhead spent heads back to the first strong pair of buds for a second flush. Fall: Leave the last flush's spent heads on for winter bud insulation; tidy in early spring.

In my garden