16 Common Japanese Maple Problems: Causes & Easy Solutions

Japanese maples are a popular choice among tree enthusiasts and gardeners alike, admired for their beautiful leaves and elegant shape.

However, like any living organism, these trees can encounter a variety of problems that can affect their health and aesthetics.

Understanding these issues is the first step toward ensuring the longevity and beauty of your Japanese maple.

Let’s take a look at the most common issues and what you can do if they arise.

Discover the best varieties, learn about care needs and possible problems, and so much more in my detailed and comprehensive Japanese Maple Guide.

1. Leaves Curling

One of the first signs of distress in a Japanese maple is curling leaves. This is often a symptom of dehydration or lack of water, especially during hot, dry periods.

It can also be a sign of a pest infestation, such as aphids, which suck the sap from the leaves causing them to curl and eventually fall off.

Solution

Regular, deep watering during dry spells can help prevent leaf curling. Mulching around the base of the tree can help retain soil moisture.

If pests are the issue, consider using an organic insecticide like this horticultural oil or introducing beneficial insects, like ladybugs, that prey on aphids.

2. Leaves Turning Brown

Browning leaves can be a common issue in Japanese maples. This is often caused by environmental stressors such as extreme temperatures, wind, and sun exposure.

It can also be a sign of overfertilization or a disease such as verticillium wilt.

Solution

To prevent brown leaves, plant your Japanese maple in a location that offers some protection from harsh afternoon sun and strong winds. Regular watering can also help, but avoid overwatering as this can lead to root rot.

If overfertilization is the issue, reduce the amount of fertilizer, and make sure that what you are using doesn’t have a lot of nitrogen.

In case of disease, a certified arborist should be consulted for proper diagnosis and treatment.

3. Leaf Scorch

Leaf scorch is often characterized by brown, dried-out patches on the leaves, which can give the tree a scorched appearance.

Leaf scorch can be caused by a variety of factors, but it’s most commonly associated with environmental stressors.

These can include exposure to extreme temperatures, excessive sunlight, strong winds, or inadequate watering.

In some cases, leaf scorch can also be a sign of overfertilization. When too much fertilizer is applied, it can lead to a buildup of salts in the soil, which can draw moisture away from the tree’s roots and lead to scorching.

Additionally, certain diseases, such as verticillium wilt, can also cause symptoms similar to leaf scorch.

Solution

To prevent leaf scorch in your Japanese maple, there are several steps you can take. First, ensure your tree is planted in a location that offers some protection from harsh afternoon sun and strong winds.

While Japanese maples do need sunlight to thrive, they can be sensitive to intense, direct sunlight, especially during the hot summer months.

Watering is also crucial in preventing leaf scorch. Japanese maples prefer evenly moist soil, so regular watering is important, especially during dry periods.

However, be careful not to overwater, as this can lead to other problems such as root rot.

If overfertilization is the culprit, reduce the amount of fertilizer you’re using. When fertilizing your Japanese maple, it’s important to use a well-balanced fertilizer and to follow the recommended application rates.

Finally, if you suspect that a disease like verticillium wilt is causing leaf scorch, it’s best to consult with a certified arborist. They can provide a proper diagnosis and recommend a treatment plan to help your tree recover.

4. Slow Growth

Japanese maples are not known for rapid growth, but if your tree seems to be growing particularly slowly, it could be due to a few factors. These include poor soil conditions, insufficient light, or a lack of necessary nutrients.

Solution

Ensure your Japanese maple is planted in well-draining soil as waterlogged soil can hinder growth.

The tree should also be placed in a location where it receives adequate sunlight, ideally, morning sun and afternoon shade.

Regular fertilization with a slow-release, balanced fertilizer (this one is highly recommended) can also promote healthier growth.

5. Pests

Japanese maples can be susceptible to a variety of pests, including aphids, scale, mites, beetles, and ants.

These pests can cause damage ranging from leaf curling and discoloration to severe infestations that can threaten the tree’s health.

Solution

Regular inspection of your tree can help catch pest infestations early. Depending on the pest, solutions may include horticultural oils, insecticidal soaps, or introducing natural predators into your garden.

In severe cases, you may need to consult with a professional arborist.

6. Diseases

Several diseases can affect Japanese maples, including verticillium wilt, root rot, cankers, anthracnose, leaf spots, Pseudomonas syringae, and sooty mold.

These diseases can cause a variety of symptoms, including wilting, discoloration, and leaf drop.

Solution

Prevention is the best approach when it comes to diseases. This includes proper watering, avoiding injury to the tree, and proper pruning practices to maintain air circulation.

If you suspect your tree is diseased, it’s best to consult with a professional arborist for diagnosis and treatment.

7. Color of Foliage

Japanese maples are renowned for their vibrant foliage. However, sometimes the leaves may not display the expected color.

This could be due to insufficient sunlight, nutrient deficiencies, or pH imbalances in the soil.

Solution

Ensure your tree is getting enough sunlight, as shade can dull the color of the leaves.

Regular fertilization can help address nutrient deficiencies, and soil testing can help identify and correct any pH imbalances.

8. Soil Issues

Japanese maples prefer well-draining, slightly acidic soil. Issues can arise if the soil is too alkaline, is too compacted, or retains too much water.

Solution

Regular soil testing can help identify any issues with pH or nutrient levels. If the soil is too compacted, consider aerating.

If drainage is an issue, you may need to amend the soil or consider a raised bed or berm.

Dark-red laceleaf-type leaves on a Japanese maple.

9. Watering Issues

Both overwatering and underwatering can cause problems for Japanese maples. Symptoms of improper watering can include wilting, leaf scorch, and in severe cases, root rot.

Solution

Japanese maples prefer consistent moisture. Water deeply and regularly, especially during dry periods, but ensure the soil drains well to prevent waterlogging.

10. Branch Dieback

Branch dieback, where branches begin to die from the tip toward the trunk, can be caused by environmental stress, disease, or pests.

Solution

Prune back dead branches to healthy wood, and ensure the tree is receiving proper care in terms of watering, sunlight, and nutrients. If dieback continues, consult with an arborist.

11. Moss Growth

Moss growth on the trunk or branches is usually not a direct threat to the tree but can indicate overly moist conditions.

Solution

Improve air circulation around the tree and ensure the tree isn’t being overwatered. If moss growth is excessive, it can be gently removed with a soft brush.

12. Lichen Growth

Like moss, lichen is usually harmless and can even add to the aesthetic appeal of the tree. However, excessive lichen growth can indicate poor tree health.

Solution

Ensure the tree is receiving proper care. If the tree’s health continues to decline, consult with an arborist.

Lichen growing on the side of a tree trunk.

13. Physical Damage to Tree

Physical damage can occur due to weather events, animals, or human activity. This can harm the tree and provide an entry point for pests and diseases.

Solution

Protect the tree as much as possible from potential damage. If damage occurs, clean up cuts and wounds with a sharp, sterilized tool, and allow the tree to heal on its own without any wound sealant.

14. Transplant Shock

Transplant shock can occur when a tree is moved to a new location. Symptoms can include wilting, leaf drop, and slowed growth.

Solution

When transplanting, be sure to adequately water the tree and consider using a root stimulator. Try to transplant in the cooler months to reduce stress on the tree.

15. Pruning Challenges

Improper pruning can lead to a variety of issues, including disease, pest infestations, and poor tree shape.

Solution

Learn the proper techniques for pruning Japanese maples, which generally involve minimal and strategic cuts. Consider consulting with an arborist if you’re unsure.

16. Environmental Stress

Environmental stress can be caused by a variety of factors, including extreme temperatures, inadequate light, pollution, and poor soil conditions.

Solution

Choose a planting location that suits the needs of a Japanese maple, provide proper care, and protect the tree from extreme weather conditions when possible.

Closing Thoughts

Caring for Japanese maples can be a rewarding experience, but like all plants, they can encounter problems.

By understanding these common issues and their solutions, you can ensure your Japanese maple remains healthy and vibrant.

Remember that the key to successful tree care is prevention and early detection. Regularly inspect your tree for signs of distress, and take action as soon as you notice anything amiss.

With the right care and attention, your Japanese maple can provide beauty and enjoyment for many years to come.