If your hydrangea suddenly starts showing brown spots on its leaves, it’s easy to panic. But don’t worry—there are a few common reasons why this happens. It could be a pest problem, a fungal infection, or just a little hiccup in your care routine. Here’s how to play plant detective, figure out what’s wrong, and get your hydrangea back to its beautiful, healthy self.
The most common culprits are:
- Fungal infections
- Pest infestations
- Common care mistakes
Dealing with Leaf Spot Fungus
If you notice brown spots right in the middle of the leaves, you might be dealing with leaf spot fungus. As the fungus takes hold, the leaf tissue in those spots gets thin and eventually starts to crumble away. To keep the infection from spreading to the rest of your garden, you’ll want to act fast.
How to treat a fungal infection:
- Prune away any affected parts of the plant and toss them in a sealed trash bag (don’t compost them!).
- If the plant is heavily infected, it’s a good idea to treat it with a fungicide to be safe.
Identifying and Treating Spider Mites
Sometimes, pests are the reason behind those ugly brown patches. Spider mites are frequent offenders here. These tiny critters are almost impossible to see with the naked eye, but they leave behind a tell-tale sign: fine, silky webbing on the leaves. If left untreated, the leaves will turn yellow first, then brown, and eventually die off.
How to get rid of spider mites:
- Use a spray treatment containing canola oil (neem oil also works great!).
- Make sure to thoroughly coat the leaves, especially the undersides where those mites love to hide.
Common Care Mistakes That Cause Browning
Sometimes the issue isn’t a bug or a fungus—it’s just a sign that your hydrangea is a little stressed. The most common cause is dehydration. Hydrangeas are thirsty plants (the “hydra” in their name is a big hint!). If they don’t get enough water, the flowers and leaves will wilt first, then the leaves will turn brown and drop off.
Check your soil moisture first. If the soil is damp but the leaves are still browning, you might have over-fertilized your hydrangea. When there’s too much fertilizer in the soil, the leaves usually start drying out from the edges inward before the plant eventually drops them.
