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Japanese maples are renowned for bringing dramatic autumn color to the garden. Their compact size, graceful habit and vivid red, orange, purple and golden yellow foliage make these ornamental trees a striking focal point in any outdoor space.

Also known as Acer palmatum trees, Japanese maples are slow growing and perfect for brightening up smaller gardens and patio areas. Although they are fully hardy to the sometimes quite harsh climates like those in the UK and North America, Japanese maples are easy to grow and simple to care for. Some common problems, however, can affect Japanese maple trees and are worth keeping an eye out for.

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If your Japanese maple isn’t looking its best, it can be a sign there is something seriously wrong with the plant.

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What Causes a Japanese Maple to Die?

There can be many reasons your Acer tree may be dying, but most of these are related to poor growing conditions. It may be that the soil around the tree is storing too much water resulting in root rot. Or perhaps your tree is suffering from the sun or wind, which can leave shrubs looking and feeling dehydrated.

Whatever the cause, it is likely the issue can be reversed when caught and treated early enough.

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How to Tell if a Japanese Maple Tree is Already Dead

The easiest way to discover whether your Japanese maple is clinging to life or has already died is to carefully cut away a little bark. Take a peak and note the color of the wood underneath. If it is green, the tree is still alive, and there’s a good chance you can nurse it back to health. If the tree appears brown underneath the bark, that part of the tree is dead. However, it is worth looking under the bark at another part of the tree before writing off the whole tree. You may find parts of the tree are healthy, and the dead parts can be pruned away.

Japanese maple trees are deciduous and enter a dormant phase in winter, when they may look dead. Most maples will begin to show signs of young leaves reappearing in early spring. If your tree shows no sign of its beautiful foliage by late spring or early summer, the tree has likely died.

James St. John, Flickr, licensed under CC BY-NC-SA 2.0. 

How Do You Revive a Dying Japanese Maple Tree?

The easiest way to prevent Japanese maples from dying is to learn what symptoms you should look out for. If caught early enough, most can be remedied, and your tree can be returned to full health.

Symptoms to Look Out For

Curling and Falling Leaves

This can be a sign that your tree is being scorched by the sun. If you don’t want to move your Acer palmatum to a shadier part of the garden, consider planting taller plants and trees around it to provide partial shade.

Brown curling leaves can also be a symptom of under-watering. Check the top layer of soil and if it feels dry, give the tree a good soak. The last thing you want is to encourage root rot, however. So ensure the soil drains well and doesn’t become waterlogged. Cultivating the surrounding soil with a garden spade or fork will help keep it draining freely.

Sagging Branches

If your tree is unhealthy, its branches might begin to sag and/or become blotchy. This can be a symptom of poor nutrition or an insect infestation. In the case of the former, feed the tree with a good all-purpose fertilizer – a slow-release granular variety is perfect.

An insect infestation can be a bit trickier to deal with. Aphids are particularly attracted to Japanese maples and prefer to settle on young shoots. The simplest way to get rid of the insects is to use a spray bottle filled with water and washing up liquid to kill the aphids and wash them away. Inspect surrounding plants and other maples to ensure the infestation hasn’t spread.

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Will My Japanese Maple Recover?

This largely depends on how quickly you’ve taken action to revive the tree and the steps you take to help it recover. Usually, Japanese maples can be nurtured back to good health once the issue has been determined and treated.

How to Keep an Acer Palmatum Tree Healthy

Like most plants, Japanese maple trees require general maintenance to keep them healthy.

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Watering

Perhaps the most important of these is regular watering. If you are in the UK or another area with lots of precipitation, your tree will be watered by nature for much of the year. But during hot and dry spells, it pays to give the tree a good drenching two or three times a month. Aim to keep the soil moist but well drained. If your Acer is in a pot or container, check there are plenty of drainage holes and that excess water can drain freely.

Feeding

Japanese maples benefit from good quality granular fertilizer. Mulch and apply fertilizer in spring to help the tree during its growth period. Avoid feeding in autumn, as this can encourage it to grow at the wrong time of year and adversely affect its course.

Insulation

Acers planted in the garden will generally be hardy to winters with temperatures of 0 to 7°C (32° – 45°F), but applying mulch in late autumn before the first frost will help protect the roots from low temperatures. Trees planted in pots or containers will need some help to survive the winter. If they can’t be moved to a greenhouse or other sheltered place, the best way to protect Japanese maple trees from frost is to insulate the pots. Use pot feet or small blocks of wood to raise the container from the cold ground and wrap it in insulation sheets or bubble wrap to prevent the worst of the cold from reaching the root base.

Choosing the Right Spot

The location of your Acer will have a significant impact on its health. Japanese maples dislike direct hot sun, preferring a spot in dappled shade. They also like to be sheltered from strong winds and thrive best in an acidic or neutral soil pH. A potted Acer tree can be moved around to find the best shady spot. But choose your location carefully when planting a Japanese Maple in the ground as they are more difficult to relocate.

Pruning

Regular pruning has several benefits, including helping air to circulate and helping prevent fungus from appearing. The best time to prune Japanese maples is during the dormant season, from November to January. Don’t get carried away, but a little pruning to remove any dead or damaged parts of the tree and any crossing branches to allow the tree to grow in an attractive shape.

As with many things, prevention is better than cure for keeping Japanese maple trees happy and healthy. In the right conditions, Japanese maple trees are easy to grow and require little maintenance. Ensuring they are planted in well-draining soil, in a spot out of harsh sunlight, and in chilly winds gives these beautiful ornamental trees the best chance at a long and healthy life.