Amelia, a Davey blog reader in California, recently asked, “My Japanese maple's leaves are turning brown at a fast rate starting on one side of the tree. This is new.... Is it due to lack of water?”
Burnt leaves usually point to a problem called leaf scorch. It comes in three forms. Find out which your tree has and what to do about it.
How to Cure Leaf Scorch and Leaf Scorch Disease
Leaf Scorch Symptoms and Causes
There are three kinds of leaf scorch: nutrient-related leaf scorch, bacterial leaf scorch and weather-related leaf scorch, sometimes called “environmental leaf scorch.”
1. Environmental leaf scorch occurs when tree leaves have literally been burned by the sun, hot temperatures or a general lack of rain.
- In these conditions, tree roots do their best to keep water flowing, but sometimes not all leaves get enough water.
- Those dehydrated leaves are the ones with brown, sometimes shriveled, tips that look burned.
- The symptoms of this are usually at the tips of the branches and on the most exposed leaves.
2. Bacterial leaf scorch looks about the same as environmental at first glance, but has a few distinctions:
- The disease starts toward the back of branches and gradually makes its way to branch tips.
- Bacterial leaf scorch comes back year after year, browning more leaves each time.
- Leaf scorch caused by, say, drought will pop up shortly after the stressful weather. Bacterial leaf scorch is timed more specifically, right around late July or early August.
3. Nutrient scorch occurs when the tree is deficient of a nutrient vital to its health–usually iron or manganese. Look for brown in-between the veins of the leaves at the tips of the branches.
I’ve seen leaf scorch symptoms. Is my tree in danger?
Environmental and nutritional leaf scorch typically aren’t a threat to trees that are established and healthy. You can find quick tips on treating these below.
Bacterial leaf scorch, on the other hand, becomes more dangerous each year. If you suspect it, talk to your arborist. If you catch it early, you can treat your tree each year to prolong its life. Or, if it’s too late, you may need to remove your tree entirely. Again, an arborist will tell you the next best step.
Environmental and Nutritional Leaf Scorch Treatment
Healthy trees, free of pests, diseases, and other stressors, are best at fighting off weather-related leaf scorch.
Help your tree maintain vigor with these steps:
- During stretches of sunny, hot, and dry days, water your tree deeply.
- Lock in soil moisture by mulching your tree.
- Fertilize trees regularly to provide needed nutrients.
- Test the soil and provide adequate micro-nutrients (iron or manganese) if the tree is nutrient deficient.
- Do a little research on your tree’s ideal growing conditions. For example, if it’s planted in a spot with full sunlight, but likes partial shade, you might consider moving it to a more suitable place.