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It is a major disappointment when you spend the whole year looking forward to your hydrangeas blooming, and when summer arrives, the leaves and flowers turn brown and crispy. You are not alone! Browning hydrangeas are a widespread issue amongst gardeners.
Hydrangea flowers and leaves commonly turn brown when the plant is not getting enough water and is exposed to too much sunlight and wind. Overfertilizing with the wrong type of fertilizer, leaf spot fungus, and late-spring frost are also reasons for hydrangea leaves turning brown.
The good news is: if you catch the problem in time, you can revive your browning hydrangeas and maybe even save the flowers. Here, we look at the different reasons that hydrangeas turn brown, how to diagnose the issue of your browning hydrangeas, and what you can do to rescue them.
Common Reasons That Hydrangeas Turn Brown
Hydrangea leaves and flowers can turn brown for a number of reasons:
- Hydrangeas are very thirsty plants that enjoy the soil being kept evenly moist. If your hydrangeas do not get enough water, the leaves and flowers will turn brown.
- Dappled shade is what most varieties of hydrangeas prefer. When hydrangeas get too much direct sunlight during the hottest part of the day, their leaves will turn brown and crispy.
- It is generally recommended to plant hydrangeas in a sheltered area of the garden. When hydrangeas are exposed to too much wind, it causes them to lose water at a faster rate, and their leaves can turn brown.
- A hydrangea growing in a pot will turn brown if the roots do not have adequate space to grow. Hydrangeas have deep, extensive root systems, so it is important to repot them into a larger container when they outgrow their pot.
- The edges of hydrangea leaves turn brown and curl when the plant is over-fertilized. Fertilizer burn is a problem for hydrangeas, especially when you use quick-release plant food.
- Hydrangea flower buds are extremely sensitive to cold and frost. An unexpected frost late in the spring can cause the flower buds to turn brown.
- Lastly, hydrangeas can develop brown spots on their leaves caused by leaf spot fungus if their foliage gets wet too often.
Why Is My Hydrangea Turning Brown?
There are clearly several reasons that hydrangea leaves and flowers turn brown. How does one work out which of the reasons applies to your hydrangeas? Here’s how you can diagnose the problem with your browning hydrangeas.
- If the soil that your hydrangea is growing in feels dry to the touch, it is probably turning brown because of under-watering. Hydrangeas need their soil to be kept evenly moist, especially when the plants are in their first year of establishment in your garden.
- If you are watering your hydrangea often enough, but it is still turning brown, consider the amount of wind and sunlight the plant is exposed to. These factors will cause your hydrangea to lose water at a much faster rate. Hydrangeas prefer growing in partial sun or dappled shade in a sheltered area of the garden.
- If your hydrangea is potted, it’s vital to know that potted hydrangeas need water much more frequently than hydrangeas growing in the ground. If you know that too little water is not an issue for your potted hydrangea, it may be that the plant is root-bound in its pot.
- Once you are certain that your hydrangea is not water-stressed or pot-bound, and its growing conditions are not the issue, have a look at where the leaves are turning brown. If they are only turning brown and crispy along the edges of the leaves, fertilizer burn is likely the problem.
- Fertilizer burn is almost certainly the culprit if you feed your hydrangeas more than twice a year and you use chemical fertilizer. The nutrients in chemical fertilizer are released into the soil very quickly – faster than the plant can use them. They build up in the soil as mineral salts and dry out the plant roots.
- If it is late in the spring and you noticed an unseasonably frosty night, your hydrangea buds are probably turning brown due to cold stress.
- If your hydrangeas leaves have brown spots on them, the issue might be leaf spot fungus. This is often the case if you water your hydrangeas from above and get the foliage wet.
What to Do About Hydrangeas Turning Brown
Once you have figured out why your hydrangeas are turning brown, it is time to do something about it! The faster you do something, the better the chances that you can save your hydrangea.
Rescue Dehydrated Hydrangeas
Cut the damaged leaves and flowers off to make your dried out hydrangea look better. Then, assess whether you need to transplant it to a shadier, more sheltered area of the garden.
Change your watering regime so that your hydrangeas’ soil does not dry out. Instead of watering with small amounts every day, water your hydrangeas deeply less frequently. This will help them grow a deeper root system and become more drought tolerant.
Save a Potted Hydrangea
A potted hydrangea with brown leaves should be repotted into a larger container. Water it frequently so that the soil does not dry out.
Help an Overfertilized Hydrangea
Flush out a fertilizer-burnt hydrangea’s soil by watering it for much longer than usual. The excess water will leach some of the nutrients from the soil.
Only feed your hydrangea in early spring and mid-summer using a slow-release organic fertilizer. Mulch your hydrangeas with compost to give the soil a natural nutrient boost.
Save a Frost-Damaged Hydrangea
Once hydrangea buds have turned brown, they definitely will not bloom. Carefully cut off damaged buds. Avoid pruning the plant too hard because you do not want to remove shoots that will still produce flowers.
When there is a frosty night forecast, cover your hydrangeas with a towel or wrap them with some burlap. This will insulate the buds and protect them.
Rescue a Diseased Hydrangea
Leaf spot fungus is not fatal to hydrangeas, but it does cause their growth to be hampered, and they may not flower as prolifically.
To deal with leaf spot fungus, cut off all yellow leaves and leaves with brown spots and dispose of them in the trash. Do not throw them in your compost heap as they will contaminate it.
Water the base of your hydrangea plants to avoid getting the leaves wet. Fungal spores can stick to leaves when they have water drops on them, so keeping the foliage dry will limit the spread of the fungus.
If leaf spot fungus remains a big problem, you may need to treat it using a fungicide. Only use a fungicide as a last resort because the chemicals in fungicides are very harmful to the soil. You need to use them very carefully and follow the product’s instructions to a T.
Hydrangea flowers and leaves turn brown for many different reasons, but most often, it is due to lack of water. These thirsty plants need a lot of water! Hydrangeas also need to be sheltered from harsh sunlight and wind that will cause them to dry out even faster.