8 Reasons Why Japanese Maple Leaves Are Curling

Maples are amazing, aren’t they? I especially have a soft spot for Japanese maples. Their compact shape and unique split leaves really stand out. But, diving into growing them can bring its own set of challenges.

QUICK ANSWER: If you notice your Japanese Maple’s leaves turning dry and curling up, there could be a few culprits. It might be the weather playing tricks, a bit too much wind, or even an unusually humid spell causing the leaf edges to curl. Sometimes, it’s not just about the climate; pests, bacteria, or fungi could also be to blame.

1. Underwatering

One common reason for leaves curling up is not getting enough water, especially when it’s sunny and hot out. And if there’s a hot wind blowing, that just makes things worse.

When this happens, the leaves might curl inwards and even get a bit burnt around the edges. But if you catch it early, you can definitely turn things around.

This issue usually pops up with maples that haven’t been in the ground long. Older trees with well-established roots are usually more resilient.

Here’s what you can do:

1. Give your maple a good drink, making sure the water really soaks into the soil around it.
2. Wait for the top 1-2 inches of soil to dry out before you water it again.
3. And, keep a close eye on the soil’s moisture level near your tree.

Read more: How often to water a Japanese maple?

2. Diseases

Diseases are another reason maple leaves might curl up, with anthracnose being a prime suspect. This disease is the work of several pathogens and poses a significant risk, especially to younger maples.

Initially, you’ll see dark spots on the leaves, leading to curling. Without intervention, it can spread to young branches, causing leaves to wither and drop. While it’s rare for anthracnose to kill a maple, it can hit young trees hard.

Here’s what you can do:

1. Ensure your maple is basking in enough sunlight.
2. Keep the area around the tree airy to allow for good air circulation.
3. Treat the tree with a multipurpose fungicide, and don’t forget to follow up with another round after some time.
4. Be mindful not to overwater your maples.

Read more: Japanese Maple Diseases With Pictures

3. Temperature stress

Sometimes, the weather likes to play tricks on us, getting really hot during the day and then surprisingly cold at night. When this happens, maple leaves might curl up, trying to keep warm. You might even see some leaves turning red or purple.

This kind of temperature rollercoaster tends to happen in late spring or early summer. It’s usually the young maples or those in pots that feel it the most. While it’s not likely to cause serious harm, the leaves might keep their curled shape all season long.

Here’s what you can do:

1. Make sure your Japanese maple gets plenty of water.
2. Give it a dose of multipurpose liquid fertilizer.
3. Consider shading your maple with a garden umbrella for about a week to give it some relief.

4. Overwatering

Overwatering or a spell of heavy rain might lead to maple leaves curling. While some maples, like the silver maple, can handle a lot of water, Japanese maples really can’t stand too much of it.

When there’s too much water, the roots can’t get the oxygen they need, leading to root rot. This shows up as yellowing and curling of the leaves.

Here’s what you can do:

1. Cut back on watering.
2. Only water the maple when the top 2 inches of soil have dried out.
3. Ensure your Japanese maple has proper drainage.

5. Excessive Sunlight

Another issue could be too much sunlight. Imagine this: it’s early spring, and the new leaves are just starting to open up under mostly cloudy skies. Then, all of a sudden, the sun comes out in full force. These young leaves, not yet accustomed to such bright sunlight, might curl inward to protect themselves from potential sun damage.

You might also notice the edges of the leaves turning brown or finding brown spots in the middle of the leaves. Often, the curling begins at the tips of the leaves.

Here’s what you can do:

1. Provide some shade for the maple to shield it from the intense sun.
2. Increase watering to help the maple cope with the heat, but be careful not to overdo it.

Read more: Can Japanese maple grow in full sun?

6. Improper Fertilization

Using too much mineral fertilizer on your maple can lead to the leaves curling and wilting.

Another issue might arise if the soil lacks essential nutrients or if they’re not accessible to the maple, often due to overly alkaline soil conditions.

Here’s what you can do:

1. Go easy on the fertilizing.
2. Use a soil acidifier to adjust the pH level.
3. Opt for a slow-release, all-purpose fertilizer and apply it no more than once a year.

Read more: What kind of fertilizer does a Japanese maple need?

7. Pest Infestation

Pests are another reason why maple leaves might start curling, and this can be particularly tough on young trees. Aphids are one of the usual suspects here. They like to hang out on the undersides of leaves, feasting on the sap.

Here’s what you can do:

1. Give your maple a spray with horticultural oil. Often, one application is all you need.
2. Alternatively, you could introduce ladybugs, nature’s own pest control, instead of using horticultural oil.

8. Transplant Shock

Transplant shock can also lead to leaf curl. When a maple is moved to a new spot, the abrupt shift in its environment can stress it out, causing the leaves to twist and drop.

Here’s what you can do:

1. It’s best to plant maples early in the spring, before their growth kicks in.
2. Be careful not to harm the roots during the transplant.
3. Provide some shade for the maple for the first few weeks after moving it.
4. Make sure to water the maple regularly, ensuring the soil doesn’t dry out more than an inch deep.

Read more: How To Reduce Japanese Maple Transplant Shock?

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