One of the critical factors for successful hydrangea bloom is when and how to prune. The key factor is whether the plant blooms on new or old wood. Do the blooms develop on this season’s new growth or last year’s mature stalks? It is always best to choose a plant that fits the space it will occupy. That way, pruning can be kept to a minimum and done only for the well being of the plant and to promote vigorous flowering.
There are five types of hydrangeas, which fall into two pruning groups.
Group I, generally, bloom on old wood. These plants produce flower buds on stems from August through October for the following summer’s blooms. If these stems are pruned in the fall, winter, or spring, the bloom buds will be removed, and there will be little or no bloom the following summer. Types in this group are:
- Hydrangea macrophylla (mophead and lacecap)Big Daddy, Homigo, Lemon Daddy, Nikko Blue, Pia, or Pistachio
- Hydrangea quercifolia (Oakleaf) Alice, Munchkin, Sikes Dwarf, Snow Queen
Group II bloom on new wood. These plants produce flower buds in the current season, beginning about a month or two before they bloom. Therefore, they can be pruned any time after they bloom and up until they begin producing flower buds. Types in this group are:
- Hydrangea arborescens (smooth hydrangea) Annabelle, Bella Anna, Invincibelle Spirit, Incrediball.
- Hydrangea paniculata (PeeGee and family) Bobo, Bombshell, Fire & Ice, Limelight, Little Lime, Phantom, Pinky Winky, Quick Fire, Sweet Summer, Vanilla Strawberry.
- Hydrangea anomala petiolaris (climbing hydrangea)
- The everblooming varieties of Hydrangea macrophylla also belong to Group II and include Forever & Ever Hydrangea Series and Endless Summer Series.
If in doubt, only prune off old flower heads and leave the rest until spring. Once June arrives, you’re safe to prune off any stems that have not produced leaves.
Watch our video to learn more.