If you are asking why do my hydrangeas only bloom at the bottom? You are certainly not the only person who has had this problem.
I had a neighbor who had that exact issue for a couple of years.
Fortunately, in his case, it was fairly easy to resolve.
Usually it can be pinpointed to one of two things, but sometimes a few other factors can come into the reckoning.
We will examine them all here.
So let’s jump in.
Why Do My Hydrangeas Only Bloom At The Bottom
Generally, if your hydrangea is only blooming at the bottom, it is either down to it being pruned incorrectly or because it has been affected by an unusually cold spell of weather late in fall or early in spring. To deal with the issue you first need to know whether your hydrangea blooms on old wood or new wood, as they will be affected differently.
REASON 1: You Might Be Pruning Them Incorrectly
If your hydrangeas only seem to bloom at the bottom, then the most likely reason is that you have been pruning them incorrectly.
To determine if this is the issue, you need to know whether your hydrangea blooms on old wood or whether it blooms on new wood.
As a quick reminder:
- Blooms on old wood: These are hydrangeas that set their flower buds late on in summer on stalks that have been on the plant since the previous year. Varieties that bloom on old wood include mophead, macrophylla, lacecap and oakleaf.
- Blooms on new wood: These are hydrangeas that set their buds on the current season’s growth. Smooth hydrangeas and panicle hydrangeas tend to bloom on new wood.
- Some varieties, like Endless Summer hydrangeas bloom on both old and new wood.
Knowing whether your hydrangea sets its buds on new wood or old wood is crucial to keeping it blooming properly each year.
That is because it informs where and when you should prune your hydrangea.
What often happens with hydrangeas that bloom on old wood, is that many gardeners innocently carry out a spring (or sometimes late fall) prune unaware that they are pruning off the current year’s buds that would have set the previous autumn.
This means you are effectively eliminating the old wood that supports new blooms.
So when should you prune your hydrangea?
Well hydrangeas that bloom on old wood should be pruned immediately after blooming in the summer, and definitely no later than the start of August.
Then as winter is coming to an end and spring is coming in, weak and damaged stems can also be pruned out.
Alternatively, you can leave the hydrangea alone all summer, fall and winter, and then cut off the old dried brown blooms in the spring when you see new blooms opening.
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If your hydrangea blooms on new wood then from a purely aesthetic point of view you want to remove faded blooms at the end of summer.
Then you can cut back the entire shrub as winter comes to an end and before new growth appears in the spring.
To err on the side of caution when I deadhead spent flowers I simply cut the peduncle (the string that connects the bloom to the stem).
That way you have peace of mind that you can never have pruned incorrectly as you haven’t touched the stem.
Pruning incorrectly is more often than not the main cause of hydrangea bushes growing in an uneven fashion and blooming only at the bottom.
So double-check whether your hydrangea blooms on new wood or old wood and then prune accordingly.
REASON 2: It Could Be Down to Unseasonably Early or Late Cold Snaps
Hydrangeas that bloom on old wood are particularly susceptible to sudden spells of cold weather in fall or a cold snap after warm weather in the spring.
Hydrangeas are slow to get conditioned to cold weather in the fall and they come out of hibernation early on in spring.
So it could be that the buds that are formed in the fall are killed by an early cold spell before they go into hibernation or by a late cold spell when they have come out of hibernation.
This can affect buds anywhere on the plant, but often buds on the lower sections of a hydrangea have more protection from the cold weather and will bloom just fine, whereas the buds on upper branches are more likely to be killed off.
Of course, unpredictable weather is exactly that, it can’t be predicted!
But if you do live in an area that is prone to these conditions I would suggest avoiding fertilizers and instead use only organic mulch year round.
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Fertilizers used three months or closer to the first frost can keep your hydrangea in ‘grow mode’.
This increases the likelihood of the buds being affected by early frosts.
Also regularly watering your hydrangea can help if late frosts are announced or you get a dry fall.
Finally there are some hydrangeas that are more equipped to deal with erratic weather conditions.
Smooth hydrangea and peegee hydrangea are both cold tolerant with Annabelle’s being particularly reliable bloomers in cold climates.
Hydrangeas that form buds on new wood are rarely affected by cold weather in the same way.
Other Possible Explanations For Why Your Hydrangeas is Only Blooming at the Bottom
Animals Could Be the Culprit
Deer and certain other animals have a taste for hydrangeas (and many other plants for that matter).
It could be that they are nibbling at the flowers.
Naturally if it was a deer or a similar animal, they would find it easier to eat the blooms at the top of the plant and leave those at the bottom alone.
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Are They Getting Enough Sun?
Hydrangeas like a mix of sunshine and shade.
Generally they prefer sun in the morning before it is at its hottest, and shade for the rest of the day.
Take a look at where your hydrangeas are situated and see if anything is preventing certain parts of them from getting the adequate balance of sunlight and shade.
Is it Too Hot?
The majority of hydrangeas prefer cool, moist shady areas, although there are certain species that are more heat tolerant.
They like rich, organic soil too.
Even if your hydrangea spends most of the time in the shade, if the climate is particularly hot and dry it may struggle and this is sometimes demonstrated in unpredictable blooming patterns.
If your hydrangeas are only blooming at the bottom, it is more than likely due to incorrect pruning or unseasonably cold weather in fall or spring.
Both of these factors will affect different types of hydrangeas in different ways, and the key to successfully diagnosing the issue generally will depend if your hydrangea blooms on old wood or new wood.
That will determine both when and how you need to prune and whether flowering buds are more likely to withstand sudden changes in temperature.
Even if your hydrangea is only blooming at the base take that as a good sign, because by following some of the steps outlined in this article you can have it blooming properly again in no time!