Hydrangeas are a very popular landscape plant because they have such beautiful flowers, and they’re generally pretty easy to take care of. But there’s also a ton of confusion about hydrangea care and how to keep them looking their best. We’ve previously covered change-color hydrangeas, so we’ll take a look at pruning here.
While they’re all related, they do not all have the same growth and bloom patterns. Some hydrangeas change color based on pH; some hydrangeas bloom on fresh growth from this year called new wood, and some flower on the growth they put out last year called old wood. It all depends on the species of hydrangea, so it’s helpful to know what you have and keep the plant info card handy.
When to Prune Hydrangeas
You can prune hydrangeas that bloom on old wood right after they finish flowering. You can prune varieties that bloom on new wood in late winter or early spring. There are six main types of hydrangeas: Macrophylla (Bigleaf), PeeGee (Paniculata), Oakleaf (Quercifolia), Smooth (Arborescens), Mountain (Serrata), and Climbing (Anomala petiolaris).
The truth is that most hydrangeas don’t require pruning. You can prune them to control the shape or manage the size and remove dead wood, but they will also grow happily and still look great if you don’t prune them.
Bigleaf, oakleaf, climbing, and mountain hydrangeas bloom on old wood and can be pruned immediately after they finish blooming before they start pushing out next years’ buds.
Each year you can take out a few of the older and thicker stalks to control the size and shape of the plant and encourage new growth. By just removing a few of the oldest and thickest stalks, you’ll ensure you still get lots of blooms the following season.
Panicle and smooth hydrangeas bloom on new wood and can be pruned in late winter or early spring. These types tolerate very hard pruning to control the size of the bush, and a bit of pruning in spring may encourage more flowers.
The main thing to remember is that all hydrangeas, honestly, don’t need to be pruned. You can deadhead them or not. You can prune them or not. If you want large bushes, keep the pruning to a minimum.
How Can I Tell If My Hydrangea Blooms on Old or New Wood?
The quickest way is to check the tag for the name of your variety. But if you don’t have the tag anymore, or it’s faded beyond recognition, there are a few other clues that will help you determine if your hydrangea blooms on new or old wood.
If you pruned your hydrangea in the spring and it did not flower that summer, then it’s likely one that blooms on old wood, and spring pruning would have removed the buds. If you prune your hydrangea hard in the spring, and it still blooms that year, then it blooms on new wood.
Check your plant when it’s blooming; you should be able to see and feel a bit of difference between old wood and new wood. Old wood should be stiffer, tougher, thicker, and more grey or brown, while new wood will be much more flexible, soft, and should still have a greenish tinge.
You can also check your hydrangea in the fall to see if any buds are starting to push out already. If there are buds already on the branches, then it blooms on old wood. If there are not yet buds in the fall, then it will push them out on new growth the following spring.
Don’t be discouraged if your shrub isn’t blooming; leave it alone for a couple of years. Sometimes there are numerous environmental factors that can affect bloom production. Leaving it alone for a while might be just what it needs to start blooming next season. If that doesn’t do the trick, then you may have other issues affecting the blooms such as watering, sun, or soil conditions.
If you haven’t added a hydrangea to your landscape yet, what are you waiting for? Stop by Ted Lare; we’ve got plenty of options available that are well-suited to our climate here in Iowa, and we can help you solve any blooming issues you may have.