Hydrangea Pruning
Timing of pruning Hydrangeas is critical. Some species produce blooms on new wood, while other species bloom on wood produced the previous season. First learn which type of hydrangea you have in your garden, then learn how and when to prune it.
Mophead Hydrangea
(H. macrophylla)
Large “mop”-like flowers
Blooms are normally blue in our soil (acidic conditions)
They will turn pink under alkaline conditions, and often in nursery pots they are pink.
Flowers on old wood typically, but some newer re-blooming varieties bloom on new and old wood.
Best in dappled shade and moist well-drained soil.
Lacecap Hydrangea (H. macrophylla, H. serrata)
As the name suggests, their flower heads have a lacy appearance and like mopheads can be blue or pink depending on soil acidity.
Flowers on old wood typically, but some newer re-blooming varieties bloom on new and old wood.
Best in dappled shade and moist well-drained soil.
Oakleaf Hydrangea (H. quercifolia)
Lacey cone shaped flower heads.
Flowers are typically pink or white.
Unlike lacecap and mopheads, flower colour is not determined by soil acidity.
The bark has an exfoliating appearance and the leaves are oak shaped with beautiful fall colour.
Flowers on old wood.
They can grow in drier soils in dappled shade.
Pee Gee Hydrangea (H. paniculata)
Cone shaped flower heads.
Flowers emerge white to lime and fade to deep pink or cream.
Flower colour is not determined by soil acidity.
Blooms on new wood.
PeeGees are the best hydrangea for full sun but prefer dappled shade.
Climbing Hydrangea (H. petiolaris)
White lacey flower heads. Flower colour is not affected by soil acidity.
Great exfoliating bark is visible in winter.
Slow to establish but a great self-clinging vine.
Fantastic climber for shade. Ideal on the north face of a building
Smooth-leaved Hydrangea or Annabelle type Hydrangea (H. arborescens)
Large round flower heads on new wood with pink to white to lime flower colour.
May require staking, but pruning hard in early spring can help plant to grow strong stems.
Prefers dappled shade and medium moisture.
When and how do I prune my hydrangea?
Late Summer or Early Fall After Flowering
Mopheads and Lacecaps Hydrangeas (H. macrophylla and H. serrata)
These hydrangeas bloom on old wood therefore prune in summer or early fall after blooming.
Cut back weak and thin shoots to the base. Remove older and less productive branches by cutting to the base. Shorten flowered stems to pairs of healthy buds.
This type of hydrangea can be renovated by cutting the shrub to the base in the spring, but there will be not flowers the following summer.
Some newer mopheads and lacecaps are rebloomers which bloom on new and old wood, these can just be deadheaded.
Oak Leaf Hydrangea (H. quercifolia)
These bloom on old wood. Prune in late summer or early fall after blooming.
Climbing Hydrangea (H. petiolaris)
These bloom on old wood. Pruning is best kept to a minimum.
Outward growing stems may need to be shortened so they do not shade plants below.
Late winter or early spring before coming out of dormancy
Smooth-leaved Hydrangea or Annabelle type Hydrangea (H. arborescens)
Blooms on new wood therefore prune in late winter or early spring.
Prune hard to promote stronger stems and better flowering.
Pee Gee Hydrangea (H. paniculata)
Blooms on new wood therefore prune in late winter or early spring.
For plants with very large flowers, pruning in later fall once plant has entered dormancy can prevent breakage from snow.
Cut annually to a woody framework to promote stronger stems and better flowering.
