I get lots of gardening questions from folks who read my social media posts, visit my website or watch my videos. I don’t mind answering them at all. But one question has been surfacing lately so I want to address it today. What’s the question? “Why Won’t My Hydrangea Bloom?”
Hydrangeas are amazing flowering shrubs that are very popular with gardeners. There are several species and cultivars of them, which is great. It’s important to note that certain species bloom on “new wood” while others bloom on “old wood.” But what does that mean?
New wood refers to new growth in the current season. Typically, the leaves emerge first, then the flower buds. So if you prune a hydrangea that blooms on new wood, that is OK. Why? When the shrub sprouts new growth, it can easily bloom on it.
As you might guess, old wood is, well, old wood. Let’s say you give your hydrangea a haircut, thinking you’re getting it all ready to bloom and grow. Unfortunately, you likely pruned off the old wood that the flower buds would have developed and bloomed on.
Which hydrangeas bloom on new wood?
- Panicle hydrangeas (H. paniculata)
- Smooth hydrangeas (H. arborescens)
Which hydrangeas bloom on old wood?
- Big-leaf hydrangeas (H. macrophylla)
- Mountain hydrangeas (H. serrata)
- Oakleaf hydrangeas (H. quercifolia)
- Climbing hydrangeas (H. petiolaris)
I personally love those that bloom on new wood because I can prune or shape the bush any time I want. But if you have one that blooms on old wood, there’s a risk. As I mentioned above, pruning the plant before it blooms means you are eliminating future flowers.
My best advice to you is to avoid pruning those that bloom on old wood. What if a branch or two gets damaged? By all means, trim them off. But generally speaking, this category of hydrangeas shouldn’t require any pruning.
Is pruning the only reason a hydrangea won’t bloom?
The short answer is no! If your plant isn’t very old, it probably isn’t ready to bloom yet. They need time (2-5 years depending on the species) to get established in your garden. Give them TLC in the form of regular watering.
Here are two other possibilities: Did your region have a really tough winter? That can set the plant back. Just continue with the TLC and it should bounce back. Or do you have deer or moose in the garden? They don’t know the rule about not “pruning” hydrangeas!
I wish all of this was easy to remember, but here’s where to start:
- Determine which kind of hydrangea are you growing. Perhaps you still have the original plant tag or you wrote it down somewhere.
- What if the plant came with the yard when you bought your house? That’s a problem! You might consider taking a leaf to your local Master Gardener program for tentative identification. This is a free service. You can find out how to contact them by doing a web search: Master Gardeners + (your county and state). For example: “Master Gardeners Spokane County Washington”
- Are you still stuck? Leave the hydrangea alone for a year and see which type of wood the flowers appear on.
- And remember that hydrangeas rarely need pruning!
Free guide from Proven Winners
The nice folks at Proven Winners Color Choice Flowering Shrubs have some great information for you. It’s called Hydrangeas Demystified and I think it’s very helpful.