Japanese Maple Overwatering Symptoms

Japanese Maple Overwatering Symptoms

Japanese maple trees are loved by gardeners for their elegance and colorful foliage. If you have visited any of the world’s most beautiful gardens, chances are you have probably seen one or several of these trees.

If you want to grow this gorgeous tree in your backyard garden, there are some basic care requirements that you need to know in order to succeed. One such is adequate watering.

Unfortunately, a lot of newbie growers often make the mistake of overwatering their Japanese maples – and too much water is the cause of several common plant diseases that destroy the vigor and beauty of these plants.

With that in mind, it is essential to know the symptoms of an overwatered Japanese maple, so that you can correct your watering mistakes as soon as possible. This guide will teach you some of the tell-tale signs to look out for, so read on! 

Japanese maple watering requirements

The Japanese maple is a gorgeous and sturdy tree that does not require a lot of maintenance. However, like most other trees or plants, it needs careful monitoring of the soil to ensure that it is getting the right amount of water. The right balance of moisture is important to prevent the roots from drying out too quickly or – on the other hand – developing root rot.

If you are planting a Japanese maple for the first time, know that the young plant will require consistent watering until its roots are fully established. Therefore, the first two years of growth are crucial. But, once the tree has reached maturity, it should be able to absorb enough moisture from the ground unassisted.

Young Japanese maple trees will need about ten gallons of water per week. Remember that the water has to be distributed evenly so that the entire root system can be deeply soaked. It is best, therefore, to use a drip hose when watering young trees. 

So, how often should you be watering your Japanese maple? In general, Japanese maples will need watering about twice a week in normal weather conditions. During the dry season, you will need to increase this to as many as four times per week to keep the tree sufficiently hydrated. During the cold season, on the other hand, you may need to reduce the watering frequency to prevent fungal diseases.

It is also very important to determine whether the soil is moist or dry before watering your Japanese maple. Since the soil’s moisture levels are largely influenced by the weather and the current season, checking the topsoil will help you know when your plant needs watering. Most growers use the finger test to determine the dryness of the top layer of soil, but we can also recommend using a soil moisture meter for accuracy and convenience.

Japanese maple – overwatering symptoms to look out for

One of the most common questions asked by novice growers is how to tell if their Japanese maple is overwatered. Too much watering is the leading cause of death among houseplants and trees. Thus, detecting the issue at the earliest stage is key to saving your Japanese maple from an untimely demise.

Here are some of the tell-tale signs of overwatering you need to watch out for:

1. Leaves turning brown or yellow

The leaves on a healthy Japanese maple tree should be shades of purple, burgundy, or red. If the leaves have unusual discolorations, such as browning or yellowing, it might be time to review your watering routine.

Roots need oxygen as well as water to stay alive. Too much water can saturate the pores in the soil, which inhibits airflow and effectively drowns the roots. And, without healthy roots, the health of the entire plant will be compromised. Eventually, your Japanese maple will lose its vigor and its leaves will begin to wilt and turn brown.

2. Root rot 

Root rot is one of the ugliest consequences of leaving a Japanese maple to drown in waterlogged soil. Unfortunately, the early signs might not be obvious, since the roots are hidden deep in the soil. The only clues your plants would show are browning or yellowing leaves, a droopy and wilting appearance, and looking sick overall. An inexperienced grower’s immediate reaction may be to give the tree more water, which would only make matters worse!

How to check for root rot:

If your Japanese maple looks unhealthy, try to inspect the roots. Remember that healthy roots should look white, firm, and numerous. If they appear black and mushy with a swamp-like odor, then your plant is likely struggling with root rot.

Root rot is a serious issue. It is mainly caused by various types of fungal spores, such as Fusarium, Clitocybe, Phytophthora, and others. Unfortunately, it is often difficult to treat fungal infections, especially if the root damage is extensive. In most cases, infected plants are best discarded to prevent any spread of the disease.

3. Verticillium wilt

Overwatering can also attract soil-borne fungi and cause verticillium wilt in Japanese maple trees. The affected plant will eventually suffer from a variety of symptoms, such as:

  • Stunted growth
  • Wilting
  • Pale-colored leaves
  • Dieback of the roots or branches

Unfortunately, it can be challenging to diagnose verticillium wilt just by looking at the plant. You will need to take samples from the infected plant and have them tested at a diagnostic laboratory to confirm this disease.

Another sad fact is that there is no available treatment for verticillium wilt in Japanese maple trees. Prevention is therefore better than cure, and providing your plant with proper care will help maintain its vigor and strengthen its immunity against diseases.

Correct sanitation practices also go a long way in preventing the disease in the first place. Avoid using potentially contaminated soil, containers, pruning shears, and other tools on healthy plants. You should also protect the tree’s trunk from injuries, as these become easy entry points for soil-borne pathogens.

Lastly, it is recommended to choose cultivars that are resistant to local pathogens present at your particular growing site. You can also practice soil solarization methods, such as breaking up the soil and heating its surface with the help of sunlight and clear polyethylene tarpaulin to eradicate any soil-borne pathogens. This effort will save you the trouble and heartache of replacing a dying Japanese maple.

How to revive an overwatered Japanese maple

Early detection is key to saving an overwatered Japanese maple. As a responsible grower, you should make it a habit to monitor the condition of your plants regularly in order to catch the early signs of problems. This way, if you notice your Japanese maple showing signs of overwatering, you might still be able to revive it.

Follow the tips below and your Japanese maple should bounce back to health within a few days or weeks:

  • Keep your plant happy by providing it with the best possible care. Your best defense against root rot, pests, and other plant diseases is having a robust and healthy Japanese maple tree. Some of the requirements to maintain your plant’s vigor include partial sunlight, proper watering, and adequate fertilizer.
  • Japanese maples love well-draining, slightly acidic soil. When planting your tree, make sure to provide it with well-aerated and nutrient-rich soil for faster and healthier growth.
  • Add compost to the soil to improve drainage. This will also allow you to check for early signs of root rot.
  • Make it a habit to check the soil before watering. As mentioned earlier, Japanese maples become more susceptible to fungal diseases and root rot if left standing in waterlogged soil for too long. Water your plant only when the topsoil looks bone-dry.
  • Repotting an overwatered Japanese maple in a new container might save it from death. Transfer the plant to a well-draining pot with fresh, well-draining soil. Do not attempt to reuse the old soil, as it is likely infected with fungal spores. If you need to reuse the old pot, make sure it is cleaned and disinfected well.
  • Lastly, know that it may not be possible to save a Japanese maple with severe root rot. If most of its roots have turned dark and mushy, you should rather discard the plant to prevent the disease from spreading. The same is advised for other fungal diseases.  

Other care tips for growing a Japanese maple

Though the Japanese maple is a low-maintenance and hardy tree, it still requires some loving care if you want to enjoy its beautiful foliage for years to come. Keep your Japanese maple happy and thriving by following these care tips:

  • Protect the foliage by shielding the tree against strong winds. Otherwise, the leaves will easily dry out and lose their beauty.
  • Spring frost can quickly damage the leaves of your Japanese maple tree. If you live in an area with cold winters, make sure to cover your trees, especially the newly planted ones, to protect them from frost.
  • Japanese maples are sensitive to extreme weather conditions. To achieve faster and healthier growth, avoid planting them during the harsh summer or winter seasons. Early spring is the best time to plant a Japanese maple.
  • Depending on your preference, your Japanese maple can be planted in a container or directly in the ground. Just make sure that it is protected from the harsh heat of the sun. Opt for a place where it can enjoy dappled sunlight, and it should thrive.


Caring for a Japanese maple tree might sound intimidating because of its size, uniqueness, and beauty. But, in reality, it is not so difficult. To maintain its charming foliage, you only need to provide the tree with a few basic care requirements. These include adequate watering and healthy, well-draining soil. Avoid overwatering your Japanese maple at all costs, in order to protect it from unnecessary diseases and root rot!

Image: istockphoto.com / plej92