How To Properly Care For A Maple Tree

Do Maple Trees Require A Lot Of Maintenance?

When planted correctly and given the appropriate care, maples are long-lived trees that require relatively little maintenance. Take care not to over do it when it comes to watering, fertilizing, and pruning. Moderation is key in looking after your maple tree.

Tips For Keeping A Maple Tree Healthy

There are quite a few things you can do to give your maple tree the best shot at living a long, healthy life. Let’s walk through some of the essentials below.

Watering a Maple Tree

As with any plant, maple trees need an adequate amount of water to survive. However, at different stages of their growth cycles, maple trees need different levels of water to stay happy and hydrated.

Watering Young Trees

Most maple trees are happiest when planted in a moist but well-drained alkaline soil and given partial shade. For the first year or two after planting, your maple will require around 11 gallons of water a week to remain healthy. We recommend investing in a tree watering bag as this will save you both time and water in the long run.

Make sure that the water is penetrating at least 10 inches below the surface in order to fully moisten the tree’s root system. Also, take care not to water too much, and allow time between waterings for the soil to drain properly.

During the cooler winter months, when trees are dormant, your maple won’t require as much watering. Provide water only when necessary to keep the soil damp. It’s also recommended to turn off any automated irrigation systems during the winter.

Watering Established Trees

After the first couple of growing seasons your maple should be well-established, and less attention to soil’s moisture will be required. However, in the absence of rainfall — especially during the warmer months while your sapling is actively growing — it may benefit from some additional water.

Fertilizer & Mulch

Older, well-established maple trees typically don’t require fertilization for healthy growth. However, young maples may benefit from fertilization, as it helps them to establish a good root system.

When To Fertilize A Maple?

Fertilize maple trees in early spring, after new leaves have just begun to emerge. Continuing to fertilize after May will impede fall color and winter hardiness. Do not fertilize drought-stressed trees. Chemical fertilizers will draw water out and desiccate your trees even further.

What Type Of Fertilizer?

Either a slow-release shrub and tree fertilizer, or a mild, organic plant food is recommended. Fertilizers that release too much nitrogen will cause the upper-canopy to grow disproportionately to the roots. This could potentially lead to root failure and cause your tree to topple over.

Where To Spread The Fertilizer?

The root zone of a maple tree generally penetrates to 4 feet or more into the soil, but the feeder roots that absorb nutrients are in the top 12 to 18 inches. Spreading fertilizer on the soil surface will be sufficient to reach the feeder roots. Distribute evenly, beginning at least 1 foot from the base of the tree and ending beyond the drip line.

Mulching

Mulching provides a variety of benefits, according to the University of Minnesota Extension, including conserving moisture, regulating ground temperature, and suppressing weed growth. Apply a 1” to 2″ layer of organic mulch in the form of cured, chipped wood or pine needles around the tree in spring. 

As the mulch decomposes, it will add vital nutrients to the soil that will benefit your maple tree. Allow wood chips to cure for at least 6 months before use. And remember to leave at least a four inch gap around the base of the tree. This is a vulnerable part of the tree, and subject to rot if it is kept damp.

Pruning

Pruning is another essential part of keeping your maple tree happy and fostering new growth. But how and when should you prune your maple tree for optimal health?

When Should You Prune A Maple Tree?

While late fall and winter are popular seasons to prune most deciduous trees, pruning maples during this time can lead to excessive bleeding of sap. This can be particularly damaging to younger trees, and can cause the tree to weaken and become susceptible to disease.

Any major pruning of a maple tree is best performed during late spring or summer, after the leaf buds have all opened. At this time, pruning won’t cause sap to bleed from cuts.

What’s The Proper Way To Prune A Maple Tree?

Young or newly planted trees require only minimal pruning to improve structure. Remove branches that are broken, and those with weak or narrow crotches. If there are branches crossing each other, leave the one that will provide the best balance to the overall structure and remove the other.

A maple tree should have only one “leader.” If two or more vertical stems appear to be competing for this role, choose the straightest and strongest candidate and remove the others.

For more established trees, prune away any dead, diseased, weak, or crossing branches first. Next, you may wish to remove some lower branches to raise the canopy. If your goal is to allow more light and air to pass through the tree, make some thinning cuts to simplify the structure.

Shaping cuts are tricky as they may leave the tree looking unnatural. Also, truncated branches may cause sprouts to shoot from the cut forming what is known as “witch’s broom.” It’s best to remove whole branches whenever possible.

Make sure your cut is beyond the branch collar and the branch-bark ridge. The branch-bark ridge is where the branch and the trunk push up bark between them as they expand. On the bottom of the branch, where it meets the trunk or another main branch, is the “branch collar.” 

Avoid cutting into the branch-bark ridge or branch collar, as the wound will not easily heal and may become an entry point for disease or decay. Use of wound paint or tar after making a cut is not recommended. It is best to allow maples to heal themselves. 

Maple trees should never be “topped.” Cutting through the central leader stem will destroy the natural shape and structure of the tree, and potentially create an entry point for decay.

Pruning a large tree will generally require climbing with special equipment, or the use of tall “orchard” ladders. Because of the danger involved, it is highly advised that you contact one of our professional arborists for pruning larger trees.

For a demonstration on the aesthetic pruning of a Japanese maple, watch this instructive video prepared by Merritt College.

What Common Issues Affect Maple Trees?

Fortunately, the majority of maple tree diseases are purely cosmetic and not life-threatening. However, there also exist infections capable of killing maple trees, and these tend to attack a tree’s internal systems.

Below is a breakdown of some of the most common maple tree diseases, beginning with the least serious ones, and then moving on those posing a greater threat.

Tar Spot

Tar spot is a non life-threatening fungal infection that affects maple tree leaves. Leaves can have one to several spots of varying sizes at a time, which begin as small yellow spots in June, and then progress to dark, tar-like spots. It may also cause leaves to drop prematurely.

This disease can affect nearly all varieties of maple, and is caused by Rhytisma fungi that grow in decomposing leaf debris. While it shouldn’t affect your trees in the long term, the best treatment is to prevent it by raking up and disposing of dead leaves in the fall. 


Anthracnose

Anthracnose is another non-fatal disease which results in mostly cosmetic damage. It is caused by a variety of fungi, and can be identified by a wide range of symptoms. Typically, affected areas may show small, dark spots and shriveled leaves with dead or brown areas.

The leaves will usually turn brown and fall off, followed by a second set of leaves which also die off. The branches can also develop cankers, which often strip them of their bark and kill them.

This condition typically affects maple trees during periods of cold, wet weather. Branches and leaves located lower to the ground and toward the inside of the tree are more susceptible to infection.

Anthracnose is commonly mistaken for tar spot. However, it inflicts much more damage because it affects both the leaves and the branches. As with tar spot, the best treatment is to take preventative measures. The Penn State Extension recommends removing fallen leaves and twigs, and pruning away dead twigs and branches.

Leaf Scorch

Leaf Scorch, according to the Morton Arboretum, is identified by dry leaves caused by unfavorable weather conditions such as excessive full sun, low moisture, high temperatures, and dry wind. It can be as moderate as a browned leaf edge, or as severe as brown, curling, dry leaves that fall off the tree. 

All varieties may be affected, but red maple trees, sugar maples, and Japanese maple trees are especially susceptible to this condition. Treatment consists of irrigation and mulching to maintain soil moisture. You can also prune any dead branches to help reduce additional stress on the tree.

The threat to your tree is low and, as scorch isn’t caused by a bacteria or a fungus, it’s not infectious. However, symptoms may indicate a more severe underlying cause such as root rot, which affects the tree’s ability to absorb water, or an insect infestation.

Powdery Mildew

Powdery mildew is another disease that generally only causes short-term, cosmetic harm. It’s cause is the Phyllactinia fungus, and it is characterized by a superficial, fine, powder-like mildew that coats the leaves. It may occur year round, but seems to favor moderate temperatures and high humidity.

All species of maple are susceptible, but Norway maple and Japanese maple are particularly vulnerable. No treatment is necessary, but the mildew can be brushed off. You can also apply horticultural oils to help prevent it from spreading.


Verticillium Wilt

The verticillium fungus is a soil-borne disease that can remain dormant for years before attacking a tree through its roots. The fungus causes the water-transporting cells of an infected tree to shut down, preventing water and nutrients from reaching the branches and leaves.

Dead leaves will fall to the ground and the fungus can be reabsorbed into the soil, potentially triggering a wider infestation.

Symptoms can include wilting, yellow or brown leaves, leaf drop, and stunted growth. It may also cause the sapwood to turn green or brown under the bark. Sometimes, whole branches or the entire crown can wilt and die in a short period of time. Symptoms typically develop in July and August, particularly during a hot, dry summer.


There is no known cure for verticillium wilt, but some trees can recover with proper care. Oregon State University recommends pruning off and burning affected limbs, preferably before leaves fall. In severe cases, the tree must be removed and the soil fumigated. 

Root Rot

Root Rot is a general term that covers several types of fungus, including formes, ganoderma, phytophthora, and laetiporus. Depending on which pathogen is affecting the maple tree, symptoms may vary from shelf-like, half-disc growths that protrude from the trunk, to cankers that bleed sap, to bright yellow or orange mushrooms.

Most common in wet, poorly drained soil areas, root rot attacks the vascular system — or water transporting tissues — of the tree. The spores are airborne and can also be carried by flying insects and soil-bound arthropods.

Similar to verticillium wilt, this disease inhibits the maple’s ability to receive the water and nutrients it needs to survive.

Unfortunately, there is no treatment for this fatal disease. Contact one of our tree care professionals immediately to ensure that the tree is in fact infected, and to have it properly removed and disposed of if necessary.

What Does A Healthy Maple Tree Look Like?

Observing the growth of your maple tree is the clearest way to recognize if it’s healthy. Trees that aren’t fully mature should exhibit yearly growth in the form of new shoots, thicker branches, and denser foliage. Leaves should always appear green and consistently abundant throughout the tree during the growing season. 

Mature maple trees should have verdant, abundant foliage with no signs of discoloration or fungal fruiting bodies.

What Does A Sick Or Dying Maple Tree Look Like?

Are you worried your maple tree might be sick or struggling? There are a few telltale signs that can indicate distress in a maple tree. Take a look at the signs below and if your tree is exhibiting either of these symptoms, don’t hesitate to reach out to us today so we can advise you on how to save your tree.

Signs On Foliage

Foliage is often one of the first indicators that something is wrong with a maple tree. If the foliage becomes distorted, wilted, discolored, or drops prematurely during a growing season, those are signs the maple is unhealthy. Causes could include pests, water problems or diseases.

Signs On The Trunk And Branches

Damaged bark and branches in the form of discoloration and legions is not normal for maples. Bark may look healthy on the outside, but a slight scratch with your fingernail or knife will reveal that it is brown underneath, meaning the wood is dying or already dead. Green wood beneath the bark indicates that it is healthy.

Cankers and fungal fruiting bodies are a clear sign that your maple tree is suffering from a fungal infection, such as verticillium wilt or root rot.

Can A Dying Maple Tree Be Saved?

While most of the diseases affecting maple trees are non-fatal, those that are life-threatening unfortunately have no known cure. The best way to keep your maple trees happy and healthy is by taking preventative measures such as: 

• Ensuring that your maple trees are receiving the appropriate amount of water
• Removing dead wood and twigs as they appear 
• Raking up fallen leaves in the fall to prevent them from decomposing around the tree and stifling nutrient absorption 

When Should You Hire A Professional To Remove A Maple Tree?

If you believe your maple may be suffering from any of the life-threatening diseases mentioned above, such as verticillium wilt or root rot, call one of our tree care professionals to have it diagnosed as soon as possible. 

If our experts determine that it is beyond saving, we will remove it safely and efficiently. A diseased maple could potentially infect surrounding trees, pose a fire hazard, or result in serious injury or property damage.