17 Common Problems With Hydrangeas and How to Avoid Them

Hydrangeas are well loved for many of their wonderful garden attributes including their ability to grow in the shade as well as their amazing flowers. Another reason is that they are relatively low maintenance once they’ve rooted and are well established.

Hydrangeas are tough and resilient plants, but novice gardeners seasoned green thumbs alike have faced some troubles with their hydrangeas. While there are many factors that go into the problems you may encounter (planting location, geographic location, climate, etc.), there are some problems that seem to be more common than others.

Luckily for us all, the majority of issues we face with our hydrangeas are easily fixed and will not result in the death of your beautiful shrubs. Let’s dive into some of the most common problems you’ll encounter when growing hydrangeas. You’ll learn why they happen, how to fix them as well as some prevention tips!

Drooping Leaves

Seeing a hydrangea full of leaves that are drooping towards the ground can be an unsettling sight for any gardener. The large leaves make this quite a dramatic sight.

The most likely cause of this is a lack of water. You will typically see these leaves drooping in the afternoon, especially if your plants are receiving too much afternoon sun. Hydrangeas are at their best planted in partial shade with four to six hours of morning sunlight. The exception to this rule is Hydrangea paniculata which loves full sun, but will still have drooping leaves if it is thirsty.

Drooping hydrangea leaves are easily remedied by good watering. When you are watering your hydrangeas it is important to avoid hitting the leaves with water. This can cause issues with the leaves such as fungal diseases. Aim your hose towards the base of the plant and water away. If you have soaker hoses or drip irrigation this is a great way to water your hydrangeas.

Hydrangeas need a good amount of water while they are getting established in your garden, and even after established will need regular watering to bloom to their fullest potential.

Yellowing Leaves

Yellowing leaves is a common issue with hydrangea gardeners. There are a few reasons why yellow leaves will plague your plants, and most of them are fairly easily fixed if you address them early enough. Here are the common causes of yellowing leaves:

Flowers Not Blooming

This is the most common complaint or question I get from friends about their hydrangeas. Sure, the beautiful leaves of this plant are lovely, but most people grow them for their stunning flowers. Seeing them not bloom can be an immediate cause for concern. This could happen for two main reasons:

Incorrect Pruning

Your hydrangea has been pruned incorrectly. If you have a hydrangea that blooms on old wood and you waited until the spring, or too late in the winter to prune, you likely snipped off your flower buds.

Hydrangeas that bloom on old wood are bigleaf hydrangea (Hydrangea macrophylla), climbing hydrangea (Hydrangea anomala), mountain hydrangea (Hydrangea serrata), and oakleaf hydrangea (Hydrangea quercifolia).

If you have these species of hydrangeas be sure to prune them shortly after blooming has ended. If you have pruned your flower buds off, don’t worry they will be back next season!

Too Much Nitrogen

Your hydrangea is receiving too much nitrogen from fertilizer. This is a common blunder. You want to feed your hydrangea so it will be strong and healthy, but flowering shrubs need phosphorus to bloom.

When you are choosing your fertilizer be sure that the P in your N-P-K is high. High nitrogen fertilizers focus on the greening of leaves. Another reason this could be happening is if your lawn fertilizer is getting into your flower beds.

Mildew on Leaves

If you notice that your leaves have a white fuzzy look to them you are likely dealing with powdery mildew. Powdery mildew is a pretty common occurrence on any shade plant, and luckily is easy to manage.

Powdery mildew is caused by a variety of different fungi. These fungi thrive in the sun, but they also need moisture to spread and are typically more aggressive on shade loving plants. Overwatering your hydrangeas, and leaving your garden untidy can lead to the spread of this fungus.

Remove any affected leaves or plant parts and discard them, (do not add them to your compost pile!). Using a copper fungicide on your plants can help get rid of this fungal disease, there are many available at garden centers.

The good news here is that powdery mildew is very rarely a life threatening issue for hydrangeas. Treat as needed and keep your garden free of leaf litter and you will be off to a good start!

Orange Spots on Leaves

This is an easy one to diagnose because it is different from other leaf spots that you may find on hydrangeas. Orange spots that form on the bottom or the underside of the leaves are hydrangea rust. The top of the leaf will turn yellow and the leaf will eventually die. This rust is another fungal disease that hydrangeas can contract.

As this disease progresses it will eventually kill the infected leaf, and the leaf will fall off. These fungal spores are spread through the splashing of water. That could be from rainfall or from watering your plants.

When you are watering your hydrangeas do your best to avoid watering from overhead. Watering at the base of the plant will help to stop the hydrangea rust before it even has a chance to spread.

Edges of Leaves are Brown

If only the edges of your leaves are turning brown this is likely from fertilizer burn. This type of fertilizer burn does not actually occur on the leaves. When too much hydrangea fertilizer is applied to any plant you risk damaging the root system. When this occurs the first sign you may notice is that the hydrangea leaves will take on a scorched look to them.

If you are not sure how much fertilizer your hydrangea will require it is best to go with the less is more approach. The application recommendations can always be found on the package of whichever fertilizer you have purchased. If you follow those instructions you will be safe.

Brown Spots on Leaves

If you are noticing brown spots on your hydrangea leaves your plant has most likely come into contact with any number of fungal diseases. Hydrangeas are susceptible to fungal diseases because of their growing requirements. The shade and moisture that they require are perfect breeding ground for fungal spores.

Most fungi spread through the splashing of water. Keeping your garden clear of any leaves or other plant material that could be carrying fungi spores is a great way to prevent their spread. Removing the spotted leaves from your hydrangea plant can also help to protect the rest of your plant.

Flowers Turning Brown

Nothing is more of a bummer than seeing your hydrangea flowers turning brown. Oftentimes this is a signal that the summer is coming to an end. However, if you notice your flowers turning brown in the middle of the summer, you will want to take a harder look at your watering schedule.

Hydrangeas should be watered regularly and even daily in the heat of the summer. If the flowers have wilted due to lack of watering one too many times they will begin to brown.

Adding mulch to your gardens will help to keep your soil moist for longer periods of time, which will help the hydrangeas out in the heat of the summer.

Holes in the Leaves

Finding holes in your hydrangea leaves is a strong sign of insect nibbling. Japanese beetles and caterpillars are commonly found on hydrangeas. Luckily these insects will not severely damage your plant, they will just take away from the beauty of your leaves.

These insects can be removed by hand, or you can treat the hydrangeas with an insecticidal soap if you would prefer.

Plant Has Become Too Large

Hydrangeas are vigorous growers and most of them are pretty quick growers. It is easy for a hydrangea to become too large for the space you have planted it if you did not plan ahead. When planting your hydrangea it is important to plan for the full size of the plant.

Occasionally you can prune your hydrangeas to size, however, this will be a recurring issue unless you make a more permanent move. Hydrangeas transplant well if it is done under the right conditions. If you need to give your hydrangea a new home, carefully dig the hydrangea out of the ground.

Make cuts into the soil outside of the canopy of the plant to avoid too much root damage. Once you have planted the hydrangea in its new home, water regularly, daily if possible, until the plant has reestablished itself. This is best done in fall or spring before the temperatures rise.

Flowers Are The Wrong Color

Hydrangea macrophylla flowers are sensitive to the pH of your soil. This means that depending if you have acidic or alkaline soil your flowers will be different colors. The best way to find out what the pH of your soil is is a soil test. These tests will give you all sorts of information about the nutrients in your soil as well.

If your flowers are pink and you were expecting blue you may need to add aluminum sulfate to your soil. If your flowers are blue and you were hoping for pink or red you may need to add garden lime to your soil.

Only Hydrangea macrophylla and sometimes Hydrangea serrata have flowers that will change color. If you have another species of hydrangea do not try to attempt to change the color by amending your soil. You could burn your plants with too much fertilizer, and mess with the overall structure of your soil. 

Wilting Flowers

Hydrangea flowers can wilt when they are getting too much sun or not enough water. Aside from Hydrangea paniculata which loves full sun, most hydrangeas only desire morning sun. If they are left in the heat for too long they will begin to wilt.

Watering your hydrangeas will keep this from happening, but it can also help to revive the wilted flowers. Typically once the hydrangeas have been watered and they are in the shade the flowers will pop back up.

If this continues to happen you may lose the flowers. You may want to consider transplanting your shrub to a cooler place to prevent the flowers from wilting again next season.

White “Fungus” Covering Stems

If you notice your hydrangea stems are covered in a white material, it may look like fungus but it is likely hydrangea scale. Hydrangea scale is an insect that feeds mostly on the undersides of hydrangea leaves, as well as the stems.

The symptoms of this feeding probably won’t be visible to you but the eggs of the insects will be. These eggs look like white fungus or mold growing on your plant. They can be difficult to remove but you can do so by hand.

Branches Are Drooping

Hydrangeas that bloom on new wood tend to have very large flowers that bloom on brand new stems. Sometimes the weight of the flower is just too much for the stem to handle. There isn’t anything wrong with your hydrangea if you notice this happening, especially after a heavy rain. There are a few things you can do to aid your plant in handling this issue though:

1. Leave older hydrangea stems during pruning.
2. This will provide newer shoots with support from older, more sturdy stems.
3. Make sure your plants are getting at least a few hours of morning sun.
4. This will help make sure the new growth is more sturdy.

Flowers Are Too Small

If your flowers are smaller than you expected this likely has to do with the plant care it is receiving. Common causes for small flowers are too little sunlight, incorrect fertilizer or incorrect amount of water.

Double check what type of fertilizer you have been using. Hydrangeas, as well as most flowering shrubs, require phosphorus to bloom. Your hydrangea may be getting too much nitrogen which will cause lush green leaves to grow but could limit your flower size.

Hydrangeas need a good amount of water. This is especially true for newer plants, as well as all plants when the summer heat cranks up. If you notice that your flowers are smaller than you expected or smaller than they have been in the past try to increase your amount of watering.

Purple Leaves

Many types of hydrangea have leaves that will turn to many different shades of red in the fall, offering something new for us to admire about them. However, if you are noticing leaves that have turned totally purple (not talking spots here) you should have a soil test done.

This is likely a lack of phosphorus in your soil. Once you have your soil test results this should be an easy fix for you.

Purple leaves can also occur if you have been trying to change the color of your hydrangea flowers. When soil is too acidic, phosphorus becomes unavailable to the plant. If this sounds like something that could be going on in your garden, you could try adding garden lime to the soil to raise the pH.

Leggy or Weak Stems

Oftentimes when hydrangeas receive too many applications of fertilizer the new growth will become lengthened and will result in leggy and weak stems. Hydrangeas are best fertilized in the spring. Do not fertilize after August. At this point in the season the hydrangeas are preparing to head into dormancy. Any extra feedings would push growth and would lead to weakened stems.

Another reason for spindly growth could be too little sunlight. When plants are not receiving enough sunlight the plant will grow and stretch towards the sunlight. Hydrangeas need sunlight for so many reasons including: strong stems and large blossoms.

This is an easy enough problem to solve if you have the room or correct spot to transplant your hydrangea into a sunnier spot. Another option is to prune whatever is growing above your hydrangeas if you are able.

Pruning and deadheading can also help with this. Deadheading your hydrangeas will simply relieve the plant of holding up the heavy blossoms. Pruning, however, can help to encourage new stronger growth.