Blooms on new wood, blooms on old wood, prune, don't prune, when to prune... how to keep it all straight?! Well, it's true, there are several types of hydrangeas and different types require different things. We will explain in this post, specifically, when or when not to prune each type, and if you should or shouldn't to get a maximum bloom. By the end of this blog post, you will have a reference for the next time you need to know if your hydrangea blooms on new or old wood (and what that means!)!
First, let's define what "blooms on old wood" and "blooms on new wood" means. Hydrangeas bloom on either, depending on type. If yours blooms on old wood, it means that you will prune it very minimally, as pruning will cut off blooms forming inside the old wood of the stems. Blooming on new wood means just the opposite- you can prune and it will not hinder the blooms, in fact, many times, pruning it can help it bloom better.
Which hydrangea are you growing? There are many types of hydrangeas; below we have laid out information about the six most common types, and the ones you will find most often at local nurseries.
Bigleaf (Hydrangea macrophylla):
Also known as mophead or lacecap, this hydrangea blooms on old wood, so you do not need to frequently prune. Avoid pruning as you will cut off the flower buds that are forming inside the stems, but if you do need to prune to maintain size/etc., it is fine to do so right after it has finished blooming for the season. Waiting to do so later in the year, however, will cut off blooms forming for the next bloom season.
Popular varieties: 'Cityline' series, 'Let's Dance' series, 'Endless Summer' collection
Panicle (Hydrangea paniculata):
Also known as pee gee hydrangea, this is another popular hydrangea to grow in our area of Middle TN! Panicle varieties bloom on new wood, so it is fine to prune in late winter/ early spring. They're probably the easiest to grow hydrangea, so if you are new to hydrangeas or do not spend much time in the garden but want the blooms, this type of hydrangea may be for you!
Popular varieties: 'Bobo', 'Limelight', 'Little Lime', 'Pinky Winky', 'Quick Fire', 'Little Quick Fire', 'Vanilla Strawberry', 'Phantom'
Smooth Hydrangea (Hydrangea arborescens):
Many of you may also know this as the Annabelle hydrangea. This variety also blooms on new wood, so you can prune in late winter/ early spring.
Popular varieties: 'Incrediball' series & 'Invincibelle' Spirit series
Oakleaf hydrangea (Hydrangea quercifolia):
Well-loved for its oak-shaped leaves, this hydrangea blooms on old wood, so do not prune unless you need to- then prune after it has finished blooming for the year.
Popular varieties: 'Ruby Slippers', 'Alice', 'Snow Queen', & 'Gatsby' series
Climbing (Hydrangea petiolaris):
Climbing hydrangeas are truly unique. They can reach 70' tall depending on variety! This hydrangea blooms on old wood, so you should avoid pruning unless you need to keep it smaller in size.
Popular varieties: 'Miranda'
Mountain Hydrangea (Hydrangea serrata):
Most Mountain hydrangeas are Lacecap, meaning their flowerheads are flatter and feature showy, large blooms on each flowerhead. Some varieties feature the large mophead flower, however. Mountain hydrangeas are typically smaller varieties of hydrangea. Mountain hydrangeas bloom on old wood and therefore should only be pruned after they've bloomed, if needed.
Popular varieties: 'Tiny Tuff Stuff'
In summary, Bigleaf varieties such as Mophead, Mountain, Climbing, Oakleaf, and Lacecap (which is a style of flower, not a variety) all bloom on old wood and therefore should only be pruned (if needed) right after they've finished blooming. Panicle and Smooth hydrangeas bloom on new wood and are best pruned in late winter.
We hope this helps clear up some of the confusion over when to prune and not prune your hydrangeas! Feel free to ask questions below and we hope to see you soon at the nursery.