Hydrangeas are like the showstoppers of the garden world.
With their big, beautiful blooms and lush green leaves, they turn ordinary yards into colorful masterpieces.
But growing hydrangeas isn’t always as easy as planting and forgetting.
In fact, many gardeners—both beginners and experienced—often make mistakes that can leave their plants wilted, flowerless, or just plain unhappy.
The good news?
Most of these mistakes are totally avoidable once you know what to look out for.
This article will walk you through the most common hydrangea growing errors and how to steer clear of them.
We’ll break down everything in simple, easy-to-understand steps so your hydrangeas can thrive—and maybe even steal the spotlight in your neighborhood.
Let’s dive into the top five mistakes to avoid when growing hydrangeas.
Planting in the Wrong Spot: Location Can Make or Break Your Blooms
Where you plant your hydrangeas is everything.
You could buy the healthiest plant at the nursery, give it all the love in the world, and still get sad-looking blooms if it’s not in the right place.
That’s how important location is.
So, what exactly makes a “good” spot for hydrangeas?
Hydrangeas like a balance between sun and shade.
If you give them too much sun, especially in hot afternoon hours, their leaves can scorch and their blooms may dry out too fast.
On the other hand, if they’re stuck in deep shade, they might grow lots of leaves but few (if any) flowers.
Most hydrangeas prefer what’s called partial shade.
That means a place where they get morning sunlight and then some relief from the heat in the afternoon—like the dappled shade of a tree.
But don’t just think about sunlight.
The soil and air around the spot matter, too.
Hydrangeas like soil that drains well but still holds some moisture.
If you plant them in a soggy, puddle-prone spot, their roots can rot.
And if the area dries out too quickly, your plant will struggle to stay hydrated.
Try planting them where they’re protected from strong winds, which can tear their leaves and knock over those big blooms.
Along fences, next to a house, or under tall trees (but not too close to tree roots!) can be great options.
Lastly, don’t plant them too close to other big shrubs or trees.
Hydrangeas need space to breathe, grow, and soak up nutrients from the soil.
Cramming them in can lead to weak growth and fewer flowers.
Bottom line?
Take your time when picking the perfect spot.
Your hydrangeas will thank you with bigger, healthier, and more colorful blooms.
Watering Woes: Too Much, Too Little, or Just Right?
Water is life for plants—but with hydrangeas, it’s all about finding the sweet spot.
One of the biggest mistakes gardeners make is watering their hydrangeas the wrong way.
Let’s break it down.
First off, hydrangeas are thirsty plants.
Their name even comes from the Greek words for “water” and “jar”—so yes, they love a good drink.
But here’s the catch: loving water doesn’t mean they want to be drowning in it.
Too much water can cause root rot, where the roots sit in soggy soil and start to decay.
This can slowly kill your plant from the bottom up.
On the flip side, not giving them enough water—especially during hot weather—can lead to droopy leaves, dried-out blooms, and stressed-out plants.
So how do you find that “just right” amount of water?
Start by checking the soil.
Stick your finger about an inch down—if it feels dry, it’s time to water.
If it’s still damp, wait a day or two.
Simple, right?
When you do water, aim for deep watering rather than light sprinkles.
That means soaking the soil so the water reaches the roots.
Try doing this two to three times a week, depending on the weather.
In really hot weeks, you might need to water more often.
And in cooler or rainy weeks, you can ease off.
Avoid watering the leaves and flowers directly.
Wet foliage can lead to diseases like powdery mildew or leaf spots.
Instead, water the base of the plant, near the soil.
Mulching around your hydrangeas can also help hold in moisture and keep the roots cool.
Use materials like bark, compost, or shredded leaves—just don’t pile it too close to the stems.
Getting the watering right can make all the difference between a tired, wilted plant and one bursting with vibrant blooms.
Hydrangeas don’t need constant babysitting—but they do need thoughtful, steady care.
Master the watering game, and you’re well on your way to hydrangea success.
Pruning at the Wrong Time: Don’t Cut Off This Year’s Flowers
Pruning can be one of the trickiest parts of growing hydrangeas.
Done right, it keeps your plant tidy, healthy, and full of flowers.
Done wrong, and you could accidentally snip off the very stems that were about to bloom.
Yes—it’s that easy to make a mistake.
Not all hydrangeas are the same, and that’s where most people go wrong.
Different types of hydrangeas bloom at different times and on different kinds of wood.
Some bloom on old wood, which means stems that grew last year.
Others bloom on new wood, meaning stems that grow this year.
If you prune a hydrangea that blooms on old wood during the winter or spring, you’re basically removing the flower buds before they ever had a chance.
No buds, no flowers.
It’s like cutting off a gift before opening it.
So, how do you know what type you have?
Here’s a simple breakdown:
Bigleaf hydrangeas (Hydrangea macrophylla), which include mophead and lacecap varieties, usually bloom on old wood.
Oakleaf hydrangeas also bloom on old wood.
These should only be pruned right after they finish blooming—usually in late summer.
That gives the plant time to grow new wood that will bloom next year.
Smooth hydrangeas (like the Annabelle variety) and panicle hydrangeas (like Limelight) bloom on new wood.
You can prune these in late winter or early spring before new growth starts.
They’ll still produce flowers later that year.
If you’re not sure what kind you have, it’s safest to avoid heavy pruning altogether.
Just snip off dead branches, spent blooms, or anything that looks damaged.
Hydrangeas don’t need major pruning every year.
In fact, many gardeners leave them mostly alone, aside from occasional clean-up.
The key is to know your plant and avoid reaching for the clippers at the wrong time.
Otherwise, you might spend the whole season waiting for blooms that never show up.
Pruning isn’t about doing more—it’s about doing it right.
Ignoring Soil pH: The Secret to Changing Bloom Colors
Did you know that hydrangeas can actually change color based on the soil they’re growing in?
It’s like a magic trick—one that most people don’t even realize they can control.
But the secret lies in something called soil pH.
Soil pH is a measure of how acidic or alkaline the soil is.
And for certain types of hydrangeas—especially bigleaf hydrangeas (Hydrangea macrophylla)—the pH level directly affects the color of the flowers.
In acidic soil (pH below 6), the blooms turn blue.
In more alkaline soil (pH above 7), the same plant might produce pink or even reddish flowers.
In between those levels, you might get purple or a mix of blue and pink on the same plant.
It’s pretty wild!
But here’s where people make a common mistake: they don’t test or adjust their soil pH, and then wonder why their flowers don’t look the way they expected.
The good news?
Changing the soil pH isn’t hard—you just need a little patience.
To make the soil more acidic (for bluer flowers), you can add things like aluminum sulfate or sulfur.
You can also mix in organic materials like pine needles, coffee grounds, or peat moss.
To make the soil more alkaline (for pinker flowers), use lime or wood ash.
But go slow—changing pH takes time, and it’s easy to overdo it.
Before making any changes, it’s smart to test your soil.
You can buy an inexpensive soil pH kit at most garden centers or online.
Knowing where you’re starting from helps you figure out how much (if anything) you need to adjust.
Keep in mind that not all hydrangeas change color.
Only the varieties that bloom in blue or pink are affected by soil pH.
White hydrangeas usually stay white no matter what.
If your goal is color control, make sure you’re growing the right type.
By ignoring soil pH, you miss out on one of the coolest parts of growing hydrangeas.
But once you understand the science, you can turn your garden into a rainbow of blooms—just by tweaking what’s beneath the surface.
Forgetting Fertilizer Rules: Feeding Without Overfeeding
Fertilizer is like a multivitamin for your plants.
It helps hydrangeas grow stronger, greener, and bloom bigger.
But just like with people, more isn’t always better.
Too much fertilizer can do more harm than good—and that’s where a lot of gardeners slip up.
When hydrangeas get too much nitrogen (a key nutrient in fertilizer), they may grow tons of leafy stems but produce very few flowers.
You’ll end up with a big, green bush that looks healthy—but where are the blooms?
On the flip side, not feeding your hydrangeas at all can leave them weak and undernourished.
Their leaves may turn pale, their growth might be slow, and the flowers may be small or sparse.
So, what’s the secret?
It’s all about balance and timing.
Most hydrangeas do well with a slow-release, balanced fertilizer—something like 10-10-10 or 14-14-14, which refers to the amounts of nitrogen, phosphorus, and potassium.
You can apply this once in the spring, right as the plant starts waking up.
Some gardeners like to give a second, lighter dose in early summer.
That’s usually enough to keep the plant going through the blooming season.
Avoid fertilizing too late in the season, especially after August.
This can push new growth that won’t have time to harden before winter, making the plant more vulnerable to cold damage.
If you’re growing your hydrangeas in containers, they may need fertilizer more often, since nutrients wash out of pots quicker than garden soil.
But even then—don’t overdo it.
Always follow the label directions, and when in doubt, use less rather than more.
Also consider using compost or organic matter to naturally boost the soil.
This adds nutrients slowly and improves the texture and health of your soil over time.
Fertilizer is a tool—not a miracle.
Use it wisely, and your hydrangeas will reward you with lush leaves and big, bold blooms.
Use it too much, and you could end up with a plant that looks good—but doesn’t perform.
Final Thoughts
Growing hydrangeas can be one of the most rewarding experiences for any gardener.
They’re beautiful, bold, and full of personality—but they do ask for a little attention and understanding.
By avoiding these common mistakes, you’ll be giving your hydrangeas the best chance to thrive.
Remember, it’s not about being perfect—it’s about being consistent and informed.
Give your plants the right spot, the right water, the right cut, the right soil, and the right food.
Do that, and your garden will be bursting with color, season after season.
Happy hydrangea growing!