Summer Care Tips for Japanese Maples

Summer Care Tips for Japanese Maples - Maple Ridge Nursery

As summer arrives with its warm, sunny days, gardening enthusiasts must take special care of their plants to ensure that everything continues to thrive. This is particularly true of Japanese maples. Japanese Maples can be vulnerable to the intense heat and dry conditions of summer. Japanese maples are generally very hardy trees that will grow fine even during the hotter summer months especially as they mature. This guide will help you understand the tips and processes to help navigate your Japanese maples through these hotter times so that they remain healthy and vibrant through the year.

Optimal Watering Practices

Watering is crucial for Japanese Maples during summer. These trees prefer consistently moist soil but can suffer from overwatering. Water frequency can vary greatly by climate and situation. Aim to water deeply up to 3 times per week for newly planted trees and no more than once per week for established trees. Rainwater typically will take care of your established Japanese maples but you want to make sure they do still get a deep watering at least once every couple weeks. Japanese maples in containers will require a deep watering nearly every other day during the hot summer months. Sunlight can also impact watering frequency as shadier areas will require less water while sunnier areas will require more. As the weather cools down in the fall, Japanese maples will require less water.

Be mindful of changing weather conditions and adjust your watering schedule accordingly. During periods of extreme heat or drought, you may need to water more frequently. Conversely, if your area receives substantial rainfall, you can reduce your watering frequency to prevent waterlogged soil.

Regularly check the moisture level of the soil around your Japanese Maple. Insert your finger or a moisture meter about 1-2 inches into the soil. If the soil feels dry at this depth, it's time to water. Keeping an eye on soil moisture helps prevent both under- and overwatering.

When you water Japanese maples, you want to make sure to give them a deep watering. This means several minutes with a hose or longer with a sprinkler for your planted trees. Deep watering for your planted Japanese maples will help promote deeper roots which will help make your tree more drought resistant. For potted Japanese maples you want to water until you see the water draining out of the bottom of the container. This ensures that the entire root system is getting hydrated.

The time of day you water can also be important. Watering your Japanese maples early in the morning is ideal. This allows the trees to absorb moisture before the heat of the day sets in, reducing the risk of evaporation. Early morning watering also helps prevent fungal diseases, which can thrive in moist conditions during the cooler evening hours.

When watering Japanese Maples, avoid using overhead sprinklers that wet the leaves if you can help it. Wet foliage can lead to fungal diseases and leaf scorch in the hot sun. Instead, use a soaker hose or drip irrigation system that delivers water directly to the root zone, ensuring efficient water use. Japanese maples are only going to drink water from the roots so there is no benefit from watering the leaves.

Mulching for Moisture Retention

Mulching is a vital practice for retaining soil moisture and regulating soil temperature. One of the most effective ways to ensure your Japanese Maples thrive during the hottest months is through proper mulching.

Mulching offers several benefits that are crucial for the health of Japanese Maples, especially during summer. It helps retain soil moisture, regulate soil temperature, suppress weeds, and improve soil structure. By conserving moisture and keeping roots cool, mulching plays a vital role in supporting the overall well-being of your trees.

Apply a 1-2 inch layer of organic mulch, such as pine bark or pine straw, around the base of the tree. Avoid piling the mulch too thickly, as this can lead to poor air circulation and moisture buildup. Applying too much mulch can suffocate roots and create a habitat for pests and diseases. Keep the mulch a few inches away from the trunk to prevent rot and fungal infections. Creating a mulch-free zone around the trunk ensures good air circulation and reduces the risk of disease. Piling mulch against the trunk, known as "mulch volcanoes," can lead to rot and pest problems. Always keep mulch a few inches away from the trunk.

Mulching significantly enhances moisture retention in the soil, which is particularly beneficial during the hot summer months. Mulch acts as a barrier, reducing water evaporation from the soil surface and helping to maintain consistent soil moisture levels. Mulch insulates the soil, keeping it cooler in the summer and protecting roots from temperature extremes. Mulch suppresses weed growth, reducing competition for water and nutrients, and ensuring your Japanese Maple receives the resources it needs.

Over time, organic mulch breaks down and may need to be replenished. Check the mulch layer periodically and add more as needed to maintain the recommended depth. Regular replenishment ensures continued moisture retention and soil health. Mulch will often need to be replenished every year or so.

Providing Shade

The majority of Japanese Maples thrive in partial shade, especially during the hottest part of the day. This protection from the hot afternoon sun helps prevent leaf scorch and stress caused by excessive sunlight. Proper shading is crucial to protect Japanese Maples from sunburn and heat stress, ensuring they remain healthy and vibrant. While some varieties can handle full sun situations, they all would appreciate a bit of a break from the hot afternoon sun whenever possible.

When planting Japanese Maples, select a location that naturally offers some protection from the harsh afternoon sun. Ideal spots include areas with dappled sunlight, such as under the canopy of taller trees, or locations that receive morning sun and afternoon shade. Positioning your Japanese Maple in a suitable spot from the start reduces the need for additional shading measures. Of course, sometimes the perfect location for a Japanese maple is unattainable. Japanese maples are hardy and adaptable trees, and many varieties can handle very sunny situations even in some of the hotter climates. It’s important to do your research to determine the proper Japanese maple variety for your desired location.

Potted Japanese Maples are more susceptible to heat stress due to their confined root systems. Move potted trees to shaded areas during the summer months, such as under a patio cover or near larger plants that provide natural shade. While they do take more care and attention, many people opt for keeping their Japanese maples in pots due to the flexibility.

Sun exposure can also have a major impact on the color of your Japanese maples. This can become a balancing act for providing your Japanese maple the perfect amount of sunlight. More sun will bring out more color in your Japanese maples especially reds and pinks. Green and white colored Japanese maples flourish in shadier environments. The colors also hold better when the roots of the tree are able to stay cooler. This is another reason why the morning sun and afternoon shade situation is so ideal for most Japanese maples. You get the sunlight during the cooler time of the day and then the afternoon shade helps keep the tree cooler during the hottest hours.


During the growing season, Japanese Maples benefit from light feeding. Use a balanced, slow-release fertilizer designed for acid-loving plants such as Happy Frog Organic Japanese Maple Fertilizer. Slow release, organic fertilizers such as Happy Frog can help promote healthy growth and vibrant foliage. Avoid heavy fertilization, as it can lead to weak, leggy growth. Fertilizers should be applied no later than early summer. Each climate and zone is different, but you want fertilizers to be done feeding in time for your trees to harden off any new growth before the first freeze of winter or fall. Most slow-release fertilizers have 3 month release so be mindful of when you typically get your first freeze of the year. We typically like to fertilize in April to ensure that our trees have had enough time to harden off new growth before our first freeze in November.

Summer Pruning

Summer is an ideal time for light pruning to maintain the shape and health of your Japanese Maple. Remove any dead or damaged branches and thin out dense areas to improve air circulation and light penetration. Avoid heavy pruning, as it can stress the tree and encourage unwanted growth. The only tool you should need for light, summer pruning would be a pair of concave cutter such as Tinyroots Carbon Steel Concave Cutters.

The first step in pruning is to remove any dead, diseased, or damaged branches. These can be easily identified by their brittle texture or discolored appearance. Cutting them off not only improves the tree's appearance but also prevents the spread of disease. Make clean cuts just above the branch collar to promote proper healing. Removing this dead wood is often the only pruning necessary during the summer.

Thinning out dense areas allows light and air to penetrate the canopy, reducing the risk of fungal diseases and promoting healthy growth. Selectively remove branches that are overcrowded, focusing on those growing inward or crossing other branches. Aim to maintain the tree's natural shape while ensuring good air circulation. During the summer you are going to want to only focus on the smaller branches.

Pruning to shape the canopy enhances the tree's aesthetic appeal. Trim back long, leggy branches to create a more compact, balanced form. When cutting, follow the branch's natural growth pattern and make cuts just above a leaf node or bud. This encourages new growth in the desired direction.

Summer is not the time for heavy pruning, as it can stress the tree and stimulate excessive growth. Instead, focus on light, selective pruning to maintain the tree's health and shape. Reserve major pruning tasks for late winter or early spring when the tree is dormant.

Pest and Disease Management

Summer is a prime time for pests and diseases. Regularly inspect your Japanese Maples for signs of aphids, spider mites, or fungal infections. Effective pest and disease management is crucial to maintaining the vitality of your Japanese Maples. If detected, treat with appropriate organic insecticides or fungicides. Maintaining good air circulation and keeping the area around the tree clean can help prevent many common issues.

Japanese Maples very hardy trees that can withstand quite a bit of trauma but they can still be susceptible to a range of pests and diseases, especially during the summer. The most common issues include aphids, spider mites, scale insects, powdery mildew, and verticillium wilt. Identifying these problems early is key to implementing effective management strategies.

Aphids are small, soft-bodied insects that feed on the sap of Japanese Maples, causing distorted leaves and a sticky residue called honeydew. Regularly inspect your trees for clusters of aphids on new growth and the undersides of leaves. Sometimes a strong stream of water can dislodge aphids from the leaves. An application of Insecticidal soap can also be helpful to remove aphids. The most natural and effective way of controlling aphids is by introducing natural predators like ladybugs to your garden.

Spider mites are tiny, spider-like pests that cause stippling and yellowing of leaves. They thrive in hot, dry conditions. Check for fine webbing and stippled leaves, especially during dry spells. Avoid spider mites by maintaining proper moisture levels and watering regularly. You can Introduce predatory mites to feed on spider mites. You can also use miticides if infestations are severe, following the manufacturer's guidelines.

Scale insects attach themselves to branches and leaves, sucking sap and weakening the tree. You can remove scale by gently scraping off scales with a soft brush or cloth. Gently scrubbing with dish soap can also be a good way of removing scale. Systemic insecticides can also be used for severe infestations, ensuring proper application to minimize harm to beneficial insects.

Powdery mildew is a fungal disease that appears as a white, powdery coating on leaves. It thrives in warm, humid conditions. Avoid powdery mildew by ensuring good air circulation around your Japanese Maples by thinning dense areas and avoiding overcrowding. Water at the base of the tree to keep foliage dry. Apply fungicides labeled for powdery mildew, following the product instructions for timing and application. Copper based fungicides are usually quite helpful for a myriad of fungal issues including powdery mildew.

Verticillium wilt is a soil-borne fungal disease that causes wilting and branch dieback. It is challenging to manage once established. Once affected you will need to remove and destroy affected branches to prevent the spread of the fungus. Proper water practices and soil drainage can help prevent fungal issues such as Verticillium wilt. Organic matter found in organic fertilizers such as Happy Frog can support the tree's immune system to help prevent these diseases.

The best way to deal with these pests and diseases is by preventing them. Conduct regular inspections of your Japanese Maples to catch problems early. Maintain consistent watering practices to keep your trees healthy and less susceptible to pests and diseases. Apply a layer of organic mulch around the base of the tree to retain moisture and regulate soil temperature. Prune away dead or diseased branches to improve air circulation and reduce the risk of infection. Effective pest and disease management is essential for maintaining the health and beauty of Japanese Maples during the summer. By identifying common issues early and implementing targeted treatments, you can protect your trees from damage and ensure they continue to thrive.

Protecting Against Heat Stress

Extreme heat can cause stress in Japanese Maples, leading to leaf scorch and wilting. The intense summer heat can pose significant challenges, causing heat stress that can affect the health and beauty of Japanese maples. Protecting your Japanese Maples from heat stress is crucial to ensure they remain vibrant and healthy throughout the season. If your tree shows signs of heat stress, provide additional shade, and maintain consistent moisture levels in the soil.

Heat stress occurs when Japanese Maples are exposed to prolonged high temperatures, leading to symptoms such as wilting, leaf scorch, and overall decline in health. Recognizing the signs of heat stress early allows for timely intervention to prevent long-term damage.

Selecting the appropriate planting location is the first step in protecting Japanese Maples from heat stress. Japanese maples thrive in partial shade, especially during the hottest part of the day. Ideal locations include areas with morning sun and afternoon shade or under the canopy of taller trees that provide dappled sunlight. Some varieties can handle more sun than others. It’s important to do your research on specific Japanese maple varieties that will fit your location before planting one.

Applying a layer of organic mulch around the base of your Japanese Maple helps retain soil moisture and regulate soil temperature. Use materials like pine bark or pine straw and spread it 1-2 inches thick. Mulch not only conserves moisture but also reduces soil temperature fluctuations, providing a cooler root environment.

Maintaining adequate soil moisture is crucial for preventing heat stress. Water your Japanese Maples deeply and regularly, ensuring the soil remains consistently moist but not waterlogged. Early morning watering is ideal to minimize evaporation and allow the roots to absorb moisture effectively. During heatwaves, you may need to increase the frequency of watering.

Pruning your Japanese Maples to improve air circulation can help reduce heat stress. Remove dead, damaged, or overcrowded branches to allow better airflow through the canopy. This helps keep the leaves cooler and reduces the risk of fungal diseases that thrive in hot, humid conditions.

Healthy trees are better equipped to withstand heat stress. Provide your Japanese Maples with balanced fertilization to support robust growth. Incorporate organic matter into the soil with Happy Frog organic fertilizer in the spring to improve its water-holding capacity and overall health. Avoid heavy fertilization during the hottest months, as this can exacerbate stress.

Regularly monitor your Japanese Maples for signs of heat stress, such as wilting, leaf scorch, or yellowing leaves. Adjust your care routine as needed. Prompt action can prevent further damage and help your trees recover more quickly. 

Protecting Japanese Maples from heat stress during the summer is essential for maintaining their health and beauty. By choosing the right location, applying mulch, practicing proper watering, and providing shade you can effectively safeguard your trees against the summer heat. Regular monitoring and timely adjustments to your care routine will help your Japanese Maples thrive. Also consider long-term strategies for protecting your Japanese Maples from heat stress. Planting drought-resistant ground covers or companion plants around your trees can provide additional shade and reduce soil temperature.   

Japanese Maple Varieties for Summer

Acer palmatum 'Red Emperor'

Acer palmatum 'Red Emperor' is an upright growing Japanese maple with large dark red leaves. 'Red Emperor' is a Japanese maple variety that can handle full sun without burning even in hotter climates. 'Red Emperor' holds a good bit of the dark red color throughout the summer as well.

Acer palmatum 'Summer Gold'

Acer palmatum ‘Summer Gold’ has arguably the best yellow spring color of any Japanese maple. ‘Summer Gold’ leafs out yellow in the spring and only gets more golden throughout the spring and summer. Fall color is orange to red. ‘Summer Gold’ is very heat tolerant and can even handle full sun in most climates. ‘Summer Gold’ will not get very large, as it will develop into a short, bushy tree.

Acer palmatum 'Tamukeyama'

Acer palmatum 'Tamukeyama' has become accepted as one of the best lace leaf varieties in cultivation, and probably the best red lace leaf for hot climates. 'Tamukeyama' not only tolerates but actually thrives in our hot Georgia summers even in full sun. ‘Tamukeyama' is a dwarf Japanese maple that is one of the fastest growing weeping Japanese maples we grow. It is slightly more irregular and upright than other lace leaf varieties. New growth is dark red in spring and holds very well especially in sunny locations.

Acer oliverianum 'Hot Blonde'

Acer oliverianum ‘Hot Blonde’ is known for its rapid growth and impressive golden color that persists throughout the year. ‘Hot Blonde’ has certainly become a favorite for us because of the strong growth as well as its incredible heat tolerance. ‘Hot Blonde’ is the perfect yellow tree for a hot, sunny southern landscape.

Acer palmatum 'Fireglow'

Acer palmatum 'Fireglow' is an upright growing Japanese maple with dark red leaves that shine in the sun. The red color of 'Fireglow' holds very well throughout summer as well. 'Fireglow' doesn’t get very big despite its upright growth habit and can handle full sun even in hotter climates.

Acer palmatum 'Seiryu'

Acer palmatum 'Seiryu' is one of the only upright growing lace leaf Japanese maples. It has a very fine and dissected green leaf that is very attractive and provides a different texture to the landscape. 'Seiryu' thrives in many different situations from full sun to full shade and can handle the heat of most climates. The green leaves of 'Seiryu' stay consistent and attractive throughout the summer.

Acer palmatum 'Moonfire'

Acer palmatum ‘Moonfire' tolerates full sun well and maintains its color in the hot summer as well as any upright variety. The foliage of 'Moonfire' comes out dark purple in spring but tends to turn redder as summer nears. Its leaves are slightly translucent and tend to glow when the sun lights them from behind.

Acer palmatum 'Sango kaku'

Acer palmatum ‘Sango kaku’ is known as the coral bark Japanese maple due to its coral red bark color in the winter. This Japanese maple is a must have for the other seasons of the year too though. In summer, 'Sango kaku' has bright green leaves and an upright, vase-shaped growth habit that looks fantastic in any landscape.

Acer palmatum 'Inaba shidare'

Acer palmatum ‘Inaba shidare’ is a red weeping Japanese maple with lacy leaves. ‘Inaba shidare’ starts out dark red in the spring and holds its color well into the summer. ‘Inaba shidare’ can take the heat of the summer and does well in sun.

Acer palmatum 'Mikawa yatsubusa'

Acer palmatum ‘Mikawa yatsubusa’ is one of the most interesting Japanese maples in existence. With its compact growth habit and dense, stacked leaf clusters ‘Mikawa yatsubusa’ is a fantastic Japanese maple tree to have around at all times of the year. ‘Mikawa yatsubusa’ is green during the summer, but its foliage is only part of the story as the structure of this dwarf Japanese maple tree is a show stopper and conversation starter that is a must have for every garden.