Hydrangeas come in all shapes and sizes, and knowing how and when to prune different varieties can feel like a challenge. Luckily, there are time-tested methods for pruning each style of hydrangea.
The first step in pruning hydrangeas is knowing what species and variety you are dealing with.
There are five common species of hydrangea that you will come across in garden centers in Northern Utah. They are: Paniculata, Arborescens, Macrophylla, Quericifolia and Climbing.
Paniculata
Botanical name: Hydrangea paniculata
Common name: Panicle Hydrangea
Pruning season: Late Winter/Early Spring (February-March)
Panicle hydrangeas are among the best hydrangeas for Utah, period. They can tolerate more sun than other species of hydrangeas, although they still do appreciate a break during the hottest part of the day. Panicles come in a wide variety of sizes, with large cone-shaped flowers that typically transition from green to white and then shades of pink later in the summer.
Varieties of Hydrangea paniculata:
- Limelight
- Little Lime
- Quick Fire
- Little Quick Fire
- Fire Light
- Fire Light Tidbit
- Berry White
- Pinky Winky
- Vanilla Strawberry
- Strawberry Sundae
- Bobo
- Little Hottie
- Puffer Fish
- Phantom
- Angel’s Blush
- Candy Apple
- Strawberry Shake
Panicle hydrangeas bloom on new wood and should be pruned back in late winter or early spring. You can cut them back to the ground, or, if you want taller plants, cut them back to one to three feet. Be sure to note what variety you are working with, as their mature heights will vary.
Arborescens
Botanical name: Hydrangea arborescens
Common name: Smooth Hydrangea
Pruning season: Late Winter/Early Spring (February-March)
Arborescens, or Smooth Hydrangeas, are another good choice for Utah. This type of hydrangea can tolerate poorer, compacted soils that many of us have to deal with, while still providing elegant mushroom-cap flowers.
Varieties of Hydrangea arborescens:
- Annabelle
- Incrediball
- Invincibell
The smooth hydrangea flowers on new wood and should be pruned down hard to 1 foot in early March. This species propagates itself by sending up many ground level suckers, which may also be cut down.
Macrophylla
Botanical name: Hydrangea macrophylla
Common names: Bigleaf, Mophead, Lacecap, French Hydrangea
Pruning season: After flowering (Early Fall)
Due to high pH, or alkalinity, in Utah soils, and our cold, dry winters, Macrophylla hydrangeas are not as reliable here as they are in other parts of the country. These types of hydrangeas typically experience winter dieback, which can be so severe that these plants often do not survive long-term here. For this reason, we recommend not pruning your Macrophylla hydrangeas unless absolutely necessary.
Varieties of Hydrangea macrophylla:
- Endless Summer series
- Seaside Serenade series
- Blue Enchantress
- Eclipse
- Nikko Blue
If you must prune your Macrophylla, prune shortly after their blooming season. Pruning in the spring would remove the flower buds, leaving you with a bloomless plant for the year. Instead, big-leaf hydrangeas are pruned in summer, after they finish blooming, and before August. These plants produce buds in late summer to early fall (August-September) that will form next year’s flowers. So prune these shrubs after they finish blooming before August. To prune, remove up to one-third of the stems each season. Start by removing the weakest shoots, both old and new ones, cutting at the base.
Quercifolia
Botanical name: Hydrangea quercifolia
Common name: Oakleaf hydrangea
Pruning season: After flowering (Early Fall)
Oakleafs are steadily becoming a more popular Hydrangea species, thanks to their unique leaf shapes which carry incredibly rich color in the fall. Their flowers are typically cone-shape, similar to Panicle varieties, in white and pinks. Oakleaf hydrangeas perform well in Utah gardens.
Varieties of Hydrangea quercifolia:
- Ruby Slippers
- Munchkin
- Snow Queen
- Gatsby series
- Jetstream
Oakleaf Hydrangeas don’t need pruning, unless they are damaged or overgrown. If you’d like to tidy up, remove the dead flower head just under the bloom. Prune only in summer right after the flowers fade. Hydrangea quercifolia blooms on old wood, meaning the previous season’s growth. By pruning in spring, you are removing the flower buds before they get a chance to bloom.
Climbing Hydrangea
Climbing hydrangeas are vigorous vines that cling to surfaces by aerial rootlets.
Botanical name: Hydrangea petiolaris, Hydrangea anomala subsp. petiolaris
Common name: Climbing hydrangea
Pruning season: After flowering (Early Fall)
Climbing hydrangeas bloom on old wood and are best pruned in summer, after flowering. Prune them lightly, as most of the buds are produced at the top of the plant. Cut back the flowered shoots to a pair of new buds. Established plants will tolerate hard pruning in spring, but extensive cutting back in one go is likely to reduce flowering for the next couple of summers.
