There are few plants that put on a summer display quite like hydrangeas, with their gorgeous, pastel coloured, cloud like blooms. But after a spell of hot, sunny weather it's common to find beautiful blooms turning brown and leaves becoming crispy.
The good news is that this doesn't usually mean your plant is dying. More often than not, it's a sign that your hydrangea has been exposed to more sun and heat than it can comfortably cope with.
In this guide, we'll explain why hydrangeas scorch in the sun, why flowers and leaves turn brown and crispy, why colour changes can happen during the summer, and the simple steps you can take to help your plants recover and thrive.
Why do hydrangeas scorch in the sun?
Hydrangeas, besides being beautiful additions to our garden, are naturally growing woodland plants in their native countries in Asia and the Americas. They thrive in woodland because the soil is consistently damp due to it being shaded, and they are protected from direct sunlight.
By biological design, hydrangeas have shallow root systems in comparison to their large leaves and blooms. The roots lose moisture much faster than they can absorb it during intense or long spells of heat.
Because of their shallow roots, hydrangeas require consistently moist soil, particularly as temperatures climb. When its topsoil dries, the plant cannot draw enough water to sustain its large leaves and blooms, causing them to burn. Any moisture in the leaves will evaporate much more quickly in the sun, hence why the edges of the leaves turn brown and curl inwards.
Hydrangeas much prefer an environment that closely mimics their natural environment. Most varieties prefer morning sun and afternoon shade, when the sun has become too hot. This makes them perfect plants for shady borders or pots that can be moved around.
Signs your hydrangea has been scorched
Hydrangeas are often described by gardeners as being “over dramatic. When they have had too much sun, they will quickly show you. Signs your hydrangea has been scorched include:
- Crispy, brown leaves - specifically the edges
- Curled leaves - its own attempt to prevent further moisture loss
- Uneven damage - the highest leaves and those receiving the brunt of the sun will look worse than leaves underneath or on the opposite side
- Premature dropping - severely scorched leaves may turn yellow or brown entirely and drop from the shrub
- Burnt petals - blooms that were colourful and plump become papery and brown
- Sun-burned flowers - blooms exposed directly to the sun will brown first, while blooms shielded from the sun remain healthier for longer
If you’re unsure whether your hydrangea is scorched or whether there’s something else going on, there are a few things to look for:
- Underwatering vs scorch - underwatering will cause wilting across the entire plant, whereas scorch usually affects the parts exposed to direct sunlight
- Fungal leaf spot vs scorch - Leaf spot, which is common in hydrangeas, looks like distinct spots with halos, whereas scorch is larger, irregular blotches with dry and crispy edges
- Fertiliser burn vs scorch - excess fertiliser can also cause brown, crispy leaf edges, but this is typically accompanied by a buildup of white crust on the soil or an excess of leaves in comparison to blooms
Tip: If you do want to give your hydrangeas a feed to give them a little boost before flowering, use a fertiliser like Allgrow with its balanced NPK of 6-2-4, so it's much less likely that they'll receive too much of one nutrient.
Why have my hydrangea blooms turned brown?
There are a few reasons why hydrangea blooms turn brown.
Heat / Sun stress
Hydrangeas naturally grow in woodland where there is more shade than direct sun. To mimic this, hydrangeas prefer morning sun and afternoon shade. Too much direct sun can cause leaves and petals to scorch and turn brown, dry, and crispy.
Even without direct sunlight, if the temperatures are too warm, hydrangeas can still turn brown. This is because their shallow root systems cannot hold enough water to sustain their large leaves and blooms in high temperatures.
Under watering
Hydrangeas need consistently moist soil for their shallow roots to provide enough water to their larger leaves and blooms. If the topsoil has become dry, they likely need watering again.
Tip: Aim to water deeply at the root, providing 1-2 inches of water a week.
Over watering
Hydrangeas being “drowned” can also cause wilting or brown leaves. Check the soil before watering and don’t water so much that there’s standing water on top.
Fungal disease
If the browning started as spots before spreading, it may be a fungal issue caused by high humidity where the water hasn’t had a chance to evaporate off the leaves, or overhead watering.
Natural aging
In late summer - autumn, blooms will naturally turn brown and dry as the plant prepares for winter
Will my hydrangea recover from sun scorch?
Hydrangeas, whilst dramatic, are relatively hardy.
Sun scorch is primarily an aesthetic issue, and so your hydrangea is likely to recover. The shrub itself is usually perfectly healthy if there are no other symptoms.
However, once the leaves and blooms have been scorched, they will not recover that season. Snip off the burnt, crispy, or brown leaves and flowers - the only slightly damaged leaves can stay, as they can still assist the plant in photosynthesis.
New foliage will emerge once temperatures cool, and it will grow healthy again the next season, provided you care for it correctly and protect it from the same levels of heat and sun.
How to prevent hydrangea scorch
If your hydrangea has already suffered from sun scorch, you’re probably going to want to know how to prevent it happening again. There are a few things you can do:
- Water deeply, a few inches at the root, not little and often
- Mulch around the roots to maintain moisture
- Give morning sun and afternoon shade where possible, even if it means moving pots or placing temporary shades over plants
- Avoid letting soil dry out completely
- Move containers during heatwaves
- Don't feed heavily during extreme heat
If you want to learn more about how to care for hydrangea before deciding whether they’re the plant right for you, read our Ultimate Guide on Caring For Hydrangeas.
Final Thoughts
Hydrangeas are surprisingly resilient. Although scorched flowers can look alarming, they're usually the result of temporary summer stress rather than a serious problem. With plenty of water, some protection from intense afternoon sun, and a little patience, your hydrangea should continue growing well and reward you with another beautiful display next season.
