6 Signs That Something's Wrong With Your Red Maple

Homeowners, schools, parks, and more choose to plant red maples for a plethora of reasons. They’re beautiful in every season, they provide privacy with their full canopies, and they tolerate a variety of soils. This ornamental tree thrives in the eastern deciduous forest and provides small-scale production of maple syrup.

Despite the hardiness of the red maple’s roots, the tree can start to die or appear sick without much warning. If you have a red maple that looks a little worse for wear, keep reading. You’ll discover a bit about the tree, six signs there’s something wrong with your red maple, and how to care for the tree.

Red Maple Summary

Acer rubrum, or the red maple, is a colorful tree that grows in Hardiness Zones between three and nine. The red maple has a medium to fast growth rate and a relatively short lifespan (between 80 and 100 years). According to data from the U.S. Forest Service, the red maple remains North America’s most common tree.

Red maple trees need both full sun and partial shade to thrive. The tree can root in a half dozen different types of soil, including:

• Acidic.
• Loamy.
• Sandy.
• Silty Loam.

While the red maple can root in these unique types of soil, owners should avoid spaces that will have poor drainage or compact soil — both of which negatively affect the red maple’s growth.

Besides its stunning colors and blooms in all four seasons, the red maple’s biggest claim to fame is its title as the state tree of Rhode Island. Historians don’t have a written account of how the state picked the tree but the majority believe the story that in the 1890s, a Rhode Island school commissioner provided students with a list of trees and asked them to pick their favorite. The red maple won, though the state didn’t officially adopt the tree as its own until 1964. Some others believe the choice simply has to do with its color; since Rhode Island’s state bird is the red hen and “Rhode Island” in Dutch roughly translates to “red island,” the tree choice made sense.

6 Signs There’s Something Wrong With Your Red Maple

While not every symptom spells the end for your red maple, some diseases or pests cause more damage than others.

Leaf Problems

Depending on the problem you see in the leaves, the culprit may be fungal, viral, or bacterial. If you’re seeing wilting or leaf spots — two problems that occur most frequently in red maples — your tree has a fungal infection.

One of the most common red maple diseases is verticillium wilt, which causes the leaves and small twigs to wilt and die. The disease is a soil-borne fungus (caused by Verticillium dahliae and Verticillium albo-atrum, among others) that infects the roots of a tree. The infection travels up the tree’s waterways, interrupting water and nutrient delivery and causing wilt.

Another common fungus that affects red maples’ foliage is Rhytisma acerinum, which causes tar spots on leaves. Thankfully, this fungus and its cousins don’t damage the red maple’s longevity — it’s usually more of a cosmetic problem than a health issue. Early tar spots may measure only a few millimeters wide and look like tiny, huddled black dots. Advanced tar spots can measure several centimeters in circumference and show significant discoloration.

What to do: If you’re sure your tree has verticillium wilt, there’s not a ton to be done. You can attempt to provide more water and nutrients but you may struggle to strike a balance between under- and over-feeding the tree.

For tar spots, you can spray fungicides on your tree to kill the parasitic growth or routinely remove the infected leaves from the tree and the ground to reduce the levels of fungi and spores.

Cracking Bark

Healthy maples should not have damaged or discolored bark. Insects, fungi, and other external forces may be at work in your red maple’s trunk, sucking sap or feeding on its nutrients.

While black knot disease is serious, owners can save their trees with fungicides that control (or at least slow) the spread of the disease.

Scales, on the other hand, are plant parasites that can kill red maples if the infestation is large enough and untreated for some time. Most owners can catch the infestation before significant damage occurs and apply an insecticide to solve the problem.

What to do: Investigate or hire a specialist to take a look to determine what sort of insect has infested the tree. Then, choose a treatment plan according to the pest. Keep an eye on your tree to determine if and when it would need re-treated.

Dead or Dying Branches

Red maples on roadways and in parks see a steep decline in their health during the winter months due to stress factors. This also occurs in the summer for dry zones that are prone to drought. Environmental stress will break branches and halt nutrient flow, which makes the red maple less apt to fight off an invasion of fungi or pests. Once affected, the tree continues to divert nutrients it would use to revive its dying branches, leaves, and twigs to protect its still-living parts. Secondary infections of root rot, twig blight, and general decay will continue to deteriorate the tree’s health unless the owner intervenes.

What to do: Urban red maple tree owners should provide nutrients and remove as much of the environmental stress as possible. Pruning the tree to avoid damage from construction, foot traffic, and more will provide the tree respite and allow it to start healing itself. Slow-release fertilizer or compost can feed the red maple an excess of nutrients that it can use to fight off infections and begin to grow again.

No New Growth

On average, healthy maple trees should add about two inches to their branch length every year. If you notice, especially for several years in a row, that your maple has stayed the same size, there’s a good chance it’s feeling sick.

Red maples can live between 80 to 100 years but they begin to decline after about four decades. Red maples that are 40 or more years old may experience no new growth as a symptom of old age.

Conversely, your red maple tree may suffer from a lack of nutrients. Identify what it needs by consulting a specialist. Or, simply purchase slow-release fertilizer or compost to provide an abundance of nutrients.

What to do: Whether your red maple is dying of old age or a lack of nutrients, you can make it more comfortable by improving its living conditions. Provide enough water and nutrients, divert any runoff or road salt away from the trunk, and fertilize until it shows signs of recovery.

Early Color Shift

The signature look of the red maple — and its very namesake — is the brilliant red color that blooms on usually green leaves during the fall months. While earlier shifting may excite some owners, the premature shift from green to red may indicate issues with nitrogen deficiency or branch dieback. Dieback, particularly, might in itself be a symptom of a deeper problem.

What to do: Based on the extent of the damage, you may be able to improve the growing conditions of your red maple. If the culprit of the early color shift is nitrogen deficiency, it’s an easy enough fix to provide the nutrients your tree lacks, and hope that solves the issues.

Generally Unhealthy-Looking Appearance

For any sickly appearance not listed above — like slimy or powdery growth on leaves, scorching, or creepy-crawly larvae — there’s a good chance it’s an indication that something is off. Because red maples have soft wood and remain short-lived compared to other species, any out-of-the-ordinary appearance may be cause for concern. When you notice your tree’s shift in health, conduct an analysis yourself or call in a specialist to help you decide the best next course of action.

What to do: Depending on what the issue turns out to be, you might use a chemical mixture, better fertilizer, need to prune, or a combination of methods to keep your red maple comfortable and alive.

How To Care for a Red Maple Tree

Red maples have the nickname of “swamp maple” because they do so well in wetlands. As such, you can easily transplant your new red maple tree into a wet site that has either full sun or partial shade. As mentioned above, red maples have a preference for most types of soil — but alkaline is not one of them. If you plant your red maple in alkaline soil, you can expect it to grow pale and sickly-looking leaves. Should you need to plant the red maple in soil that isn’t wet or moist, you’ll need to provide it with additional nutrients and frequent watering.

Your red maple needs pruning to grow structurally sound. Generally, larger maple trees over five years old should have between five and eight main branches. Younger trees can have three to four. Limiting the number of main branches allows the tree to grow in the proper shape and distribute nutrients evenly. To ensure the number of branches stays between three and eight, prune away new shoots that grow from the middle of existing branches or that sprout from the trunk. New shoots should only grow from the end of established branches.

Preventative Measures

Following the proper care instructions for feeding, watering, and pruning your red maple remains the best way to prevent disease. The healthier the tree is, the easier it’ll be able to fight an infection or infestation. When it begins to feel sickly, it has much more trouble getting its nutrients where they need to be.

Slow-releasing fertilizer, pruning dead, dying, and infected branches, and applying insecticides and fungicides when necessary are three other options red maple owners have to prevent significant damage to their trees. Quick-release fertilizer typically has harmful chemicals, so avoid using it and opt for compost instead.

Finally, you can attempt to create a better environment for your red maple. Cold climates with dry air and lots of wind can spell death for red maple, so building a fence or facade around the trunk and branches can buy a few extra years of life.

Keeping Your Red Maple Healthy

While you can’t bring your red maple back to life once it’s begun its descent, you can make it comfortable and provide the nutrients it needs to live out the rest of its life. As a soft maple, red maple trees can weather many soils but struggle to protect themselves once an outside force compromises the trunk, bark, or branches.

The photo featured at the top of this post is © KungChuyada/Shutterstock.com