A Hydrangea that doesn’t bloom can be very frustrating, especially if it used to bloom and now it doesn’t any more. If your hydrangeas aren’t blooming here are some of the most likely reasons why.
Why Aren’t My Hydrangeas Blooming?
1. Frost Damage
I’m putting this at the top of the list, even before improper pruning. That is how often I see this as the problem. If you have a Hydrangea that blooms on old wood in a colder climate (zone 5 or colder), the flower buds can get damaged from frost. That means you’ll have a season with lush green leaves but no flowers. Sometimes, when winters have been cold with little snow protection, even the branches won’t survive the winter and in spring you’ll be left with a bunch of dead branches.
You may be wondering why this wasn’t a problem when the plant was younger. The most likely reason is because it was lower to the ground and was more protected when it was younger. It probably even spent most of the winter protected in snow. Now that it is larger, branches are further away from the ground and more exposed to wind and cooler temps.
For zones 5 and colder I usually recommend avoiding hydrangeas that bloom on old wood, but depending on your microclimate you may have success with them in your landscape. Also, covering your hydrangeas during the winter will help protect them from severe cold.
2. Incorrect Pruning
Incorrect pruning, specifically incorrect timing of pruning, is another common reason why your hydrangea isn’t blooming. Some Hydrangeas bloom on new wood, which is the current seasons growth, while others bloom on old wood, which is last seasons growth. New wood hydrangeas should be pruned in early spring before flower buds develop. Old wood hydrangeas need to be pruned in late summer/early fall immediately after flower blooms fade but before new flower buds form. Check out When and How to Prune Hydrangeas if incorrect pruning could be the reason why your Hydrangeas aren’t blooming.
3. Deer
Deer love to feed on flower buds, especially in early spring has they become large and succulent. Consider using DeerPro Spring and Summer spray to protect hydrangeas. You can also use light weight bird netting that is nearly invisible to the eye. A combination of both the DeerPro and bird netting works best.
4. Plant Is Young
If you have a younger plant, it may take a couple of years for the plant to get established before setting flower buds. It may even bloom in a pot, but once it gets planted into the landscape it can take a couple of years to get the roots established in its new location before flowering.
5. Plant Is Overgrown
If you’ve left your hydrangea to grow year after year without any pruning and you’re seeing less and less blooms, it might be time to take out the pruners and give your hydrangea a reset. Old branches can become unproductive and you need to create space for newer more productive branches to grow. Overall, you want to thin out the plant, bring it back down to size, and reduce the number of branches. Too many overgrown branches could make the plant focus more on leaf growth than forming flower buds.
6. Lack of Sun
Hydrangeas often get associated with the shade garden, but too much shade may prevent your hydrangea from blooming. 4-5 hours of sun is best, and sometimes required for your hydrangea to bloom. Just avoid full exposure in the heat of the day. Broken sunlight is usually best.
7. Incorrect Fertilizer
Fertilizing with a high nitrogen fertilizer will encourage the plant to focus on green leaf growth instead of flower production. Instead, use a fertilizer that’s meant for hydrangeas such as Holly-Tone 4-3-4.
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Linda says
Hi Mark,
I have 3 Limelight hydrangeas which were planted nearly 3 years ago in late November 2021. They came back nicely in 2022 and 2023 and bloomed both years, but didn’t gain too much height and width. This year, 2 of the three are filling in nicely but one looks a little straggly. They have not set blooms yet. I have not fertilized them since they were planted. When and what type of fertilizer should I use? I read elsewhere Limelights should be fertilized in April and June and suggested using a 10-10-10 water soluble fertilizer or Holly tone. What would you recommend?
Linda