Who doesn’t love hydrangeas? With their giant mopheads of icy blue, soft mauve or creamy white flowers, it’s no wonder they’re one of the most popular flowering shrubs out there.
So, when summer rolls around, and you’re left staring at a big, green shrub with nothing but leaves, the word disappointed doesn’t even begin to cover it.
I mean, don’t get me wrong, hydrangeas are lovely without flowers, lush and emerald green, but no one grows hydrangeas for the foliage alone.
So what gives?
I promise your favorite flowering shrub isn’t being difficult just to spite you. There are actually several common reasons why this happens. Luckily, most all of them are pretty easy enough to fix once you know what you’re looking for.
If you’ve got a sulky hydrangea shrub this summer, keep reading.
1. There’s Too Much Nitrogen in the Soil
Perhaps you went a little heavy-handed with a fertilizer high in nitrogen? While nitrogen is great for beautiful foliage, your shrubs also need phosphorus and potassium for blooms. A balanced fertilizer (10-10-10) is great for giving your shrubs all the nutrients they need. I like to use Espoma Garden Food.
Another common culprit that many don’t think of right away is their lawn. If you use a lawn fertilizer too close to a hydrangea, you’re likely giving it an extra boost of nitrogen whether it needs it or not.
Related Reading: How & When to Fertilize Hydrangeas for Vibrant Summer Blooms
The Fix
Back off the nitrogen and switch to a balanced fertilizer (such as this one) or one that’s higher in phosphorus and potassium, specifically phosphorus.
2. The Right Hydrangea in the Wrong Climate
First things first, it’s important to know what type of hydrangea you’re growing. Some types bloom on old wood, others on new wood. When it comes to climate, it matters more than you think.
Bigleaf hydrangeas (Hydrangea macrophylla) and oakleaf hydrangeas (H. quercifolia) bloom on old wood (last year’s growth). Panicle (H. paniculata) and smooth hydrangeas (H. arborescens) bloom on new wood (this year’s growth).
That means that if you live in a colder zone (like 5 or lower) and you’re trying to grow an old-wood bloomer, the flower buds are likely getting zapped over the winter. Come spring, there’s nothing left to bloom. So, if you planted a gorgeous blue hydrangea last year and it bloomed beautifully, only to ghost you this year, this could be why.
The Fix
Try a cold-hardy variety that blooms on both old and new wood (like these Endless Summer series), or go with a reliable bloomer like Limelight (panicle) or Annabelle (smooth).
3. Spring Frost or an Especially Hard Winter Killed the Buds
We’ve already talked about growing the wrong hydrangea in the wrong climate. But what if you had an unexpectedly harsh winter or a couple of ill-timed late spring frosts?
If your hydrangea looks perfectly healthy but didn’t bloom this year, take a look at the stems. On old-wood varieties, you might see stems that look okay at a glance but were damaged by cold. Spring frosts can also zap newly emerging buds without damaging the plant overall.
The Fix
Consider covering your hydrangea in burlap in the fall to protect it over winter. In early spring, cover your hydrangea if a frost is in the forecast, especially if buds are starting to swell. A simple sheet will do.
4. You Pruned at the Wrong Time of Year
This is a lesson you only need to learn once. (And so many of us have!)
There’s a short window for when you can prune old-wood blooming hydrangeas. Beyond that, they start putting their energy into growing the flower buds for the following season. This means that if you prune an old-wood blooming hydrangea in the fall or early spring, you’re literally cutting off next year’s flower buds.
The Fix
Only prune old-wood bloomers immediately after they finish flowering. New-wood types can be pruned in late winter or early spring without worry.
Read Next: How to Prune Hydrangeas in Late Winter (No Matter What Type You Have)
5. The Local Fauna Loves Your Hydrangeas Too
If your buds disappear overnight, it might not be frost or pruning. It’s more likely you’ve got a four-legged lawn mower chowing down on your hydrangeas. Deer are the usual subjects, but rabbits enjoy the tender buds and stems of hydrangea, too.
The Fix
Install fencing or use deer repellents (make this one with only four common ingredients), especially in spring when buds are just forming.
6. It’s Not Getting the Right Amount of Sun at the Right Time
Most hydrangeas prefer sun and shade. Getting the mix right can be a bit tricky. If your plant is stuck in dense shade for most of the day, it might not be able to store up enough energy to bloom. On the other hand, if it’s in full sun all day, especially in hotter climates, this can stress the plant, making it less likely to bloom.
The Goldilocks sun and shade treatment for hydrangeas is bright sun in the mornings, fading to afternoon shade.
The Fix
Keep in mind that shade changes over the years when you have many different plants in your yard. If your hydrangea looks otherwise healthy but won’t bloom, check to see if a nearby tree or a taller shrub has grown up and cast new shade or whether your plant might benefit from being moved to a spot with dappled light or gentler morning sun.
7. It’s Settling In Still
If your plant is new, keep in mind that hydrangeas can take a couple of years to settle in and bloom consistently. If you bought your shrub and it was covered in blooms, keep in mind a lot of work went into growing and blooming when you picked it out at the nursery. It needs time to get established and store energy for blooms.
And gift hydrangeas—the kind you buy blooming in a pot around Easter or Mother’s Day—are often forced to bloom indoors and aren’t always bred for outdoor performance. You might want to check out Mickey’s guide on what to do with these types of hydrangeas.
The Fix
Be patient, grasshopper. Make sure your plant is well-watered and mulched, but don’t expect blooms in the first year or two after transplanting. It will happen; give it time.
8. Pests or Disease are Causing Stress and Damage
Insects, fungal infections, or even root rot can drain the plant’s energy reserves and leave it too stressed to bloom. While it takes a lot of damage to prevent the plant from blooming, if your plant didn’t bloom and isn’t looking so hot, these problems are worth considering.
The Fix
Check for signs of powdery mildew, black spots, root rot, or insect damage. Treat accordingly, and give your hydrangea time to bounce back.
One Thing That’s NOT the Problem
Let’s clear up one common myth: soil pH does not affect whether or not your plant blooms, only the color of the blooms. You can turn a bigleaf hydrangea blue with more acidic soil (low pH) or pink with more alkaline soil (high pH), but it won’t do a thing to encourage more flowers.
At the end of the day, hydrangeas aren’t really difficult—they’re just particular. They like things to be just so. But once you figure out what makes yours tick, it will reward you with blooms as big as dinner plates.
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