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Red maples are known for their beautiful red foliage in the fall, making any landscape look like a dream.
So, to see them turning green and lose this red color can be such a disheartening experience, and most gardeners would be at a loss of what they can do to save their red maple.
Are you facing a similar issue? I have come to learn that trees are very easy to maintain. And once they establish, it’s almost impossible to kill them.
But to give them the care they need, you must understand how you can cater to their unique aspects.
And in the case of the red maple, you must understand why this tree turns red and what could overturn this change.
The red maple may be turning green due to seasonal changes, the tree still being young, not the right light exposure, too much heat, not enough nutrients and too much fertilizer.
This guide gets into this in detail:
Why Is Your Red Maple Turning Green and How Can You Fix It?
People who landscape with red maples know that this tree’s leaves turn red in the fall. Sometimes, the hue can be orange or yellow.
You get the gist – there is a color change that makes these trees the go-to for people looking to impart character in their outdoors. But what gives the red maple this red color?
Anthocyanin – have you ever heard of this pigment? The red color you observe on red maples comes from this pigment.
It is present in the water-holding structures of the plant cells, i.e., the vacuoles. But for the most part, you will hardly know it is there.
This color becomes more prevalent in the fall because the chlorophyll in the leaves breaks down. And this increases the level of this pigment, which absorbs blue-green wavelengths, reflecting a red hue.
It’s all science! Thus, any change you see in your tree’s leaves will result from a disruption of this natural order. We can now discuss what can get in the way of these changes:
1) It’s Part of the Seasonal Changes
Red maples are called so because of their red foliage in the fall. But as soon as the leaves fall off this deciduous tree, there goes the color in the leaves.
Instead, what you see are reddish stems in the winter. And when spring comes along, the tree produces small red flowers.
At this stage, its leaves would be green as the red maple tree would rely on chlorophyll to make food to sustain the growth of the blooms.
And in the summer, leaf production would still be a focal point for the tree. As such, the leaves would still be green. The red color then sets in once fall begins because the tree no longer focuses on making food to sustain its leaves.
Instead, the tree starts preparing to lose its leaves and hibernate in the winter. And anthocyanin finally gets a chance to shine.
What can you do about natural changes? Nothing. You can’t change the science behind the red maple. And all you can do is wait until the next fall season and ensure the tree is healthy enough to produce healthy red foliage.
But what if seasonal changes are not to blame for the red maple leaves turning green? Then it will be time to consider the factors below:
2) The Tree is Still Young
Most people hope that their red maples will start producing red leaves during the first fall. But that is not always the case. Sometimes, a tree takes a while to acclimate to its new environment.
And as it does this, it spends its energy on establishing a healthy root system and warding off pests and diseases. Thus, this could be the issue if your red maple is young and has a fast growth rate with few or no red leaves.
How Can You Fix This?
This issue often fixes itself. At some point, the red maple establishes and slows its roll. And that gives it enough energy to focus on producing healthy leaves that turn red in the fall.
If a year or two go by, and your tree still doesn’t have red foliage in the fall, you should look into factors such as:
- Does the tree have enough access to the sun? (I will get into this in the next section)
- Does the tree get enough water? Your red maple should be in slightly moist soil. Thus, you should water it whenever the top two inches of soil are dry during its active growing season. Cut back in the winter.
- Is the tree growing in slightly acidic to neutral soil? Alkaline conditions induce chlorosis which affects the uptake of nutrients and slows the tree’s development.
Often, a tree’s inability to establish well enough to produce healthy leaves and go through the seasonal changes comes down to a deficiency in one of these needs.
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3) The Tree Lacks Adequate Light Exposure
Did you know that light plays a vital role in producing anthocyanins? Without adequate access to light, the absorption of the blue-green wavelengths is not optimal.
Thus, you may find that a mature tree with access to enough water and nutrients still does not turn red.
Dealing with Light Issues
How much light does the red maple need? This tree can grow well in USDA zones 3 to 9 and prefers full to partial sun.
Trees in lower zones experience cooler climates and should thus have full sun exposure, i.e., at least 6 hours of unobstructed access to bright and direct light.
Under these conditions, they photosynthesize well, paving the way for the loss of chlorophyll and the dominance of the anthocyanins.
Red maples like growing in the full sun. But in hotter climates, this exposure can be too much and damage the leaves.
As such, when growing these trees in higher USDA zones, you should stick to partial shade – this is exposure to at least 4 hours of bright and indirect light.
Where can you get this kind of sun exposure?
- If you live in the cooler zones, you can place your red maple in the south, where it can get full sun exposure, and
- If you live in a hot climate, you can place the tree in the east, where it can get access to the morning sunshine while avoiding the hot afternoon rays.
Red maples do well in areas with bright and sunny days coupled with cold nights. And that’s what fall offers these trees.
The more light the tree gets, the more anthocyanins it can produce. But there is a limit to how much light the tree should get, as I detail next.
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4) It’s Exposed to Too Much Heat
High temperatures can threaten healthy tree development, and the red maple is no different. While this tree enjoys full sun exposure, such access to light in the higher USDA zones can be too much for it to bear.
If you notice signs such as these below, you can tell that the tree has suffered a water loss greater than its water absorption:
- Leaf loss,
- Brown patches on the leaves,
- Crisping of the leaves,
- An onset of paleness in the leaves, and
- Cracking soil.
If this is the case and you have watered the tree diligently, the site where you’ve planted it may receive too much sunlight.
What Can You Do?
You can try and shield the tree by applying mulch around its base. But if this does not work, your best bet lies in transplanting the tree come spring.
When doing so, position the tree towards the east of the garden to protect it from the afternoon sun. Then you can wait for red leaves in the fall.
Please note that transplant shock can also hamper the production of anthocyanins, so you may need to wait one more year. But it will be worth it.
5) It Needs More Nutrients
The red maple is a forgiving plant that rarely needs fertilization. However, it may exhibit signs of nutrient deficiencies. These include:
- Yellowing of the leaves,
- The production of small-sized leaves, and
- Stunted growth.
A distressed tree will not focus on producing anthocyanins as it will be more concerned with its immediate nutritional needs.
Feeding the Red Maple
Before feeding your tree, you should conduct a soil test to gauge what the tree has and what it lacks. Your tree needs nitrogen, phosphorus, and potassium, abbreviated as NPK in commercial feeds.
When choosing a feed, go for NPK formulas with ratios such as 10-4-6 or 16-4-8, enabling the tree to develop healthy roots and shoots.
Be sure to follow the instructions laid out by the manufacturer and only feed the tree in the spring. And unless your tree shows signs of immense nutritional deficiencies, as shown on the soil test, dilute the feed to half of its strength.
6) You Fed It Too Much in the Spring
Too much feeding can derail the tree’s development. When the soil has too much of an NPK nutrient, that gets in the way of absorbing other macro and micronutrients.
Thus, the tree does not grow healthily, which interrupts the seasonal color changes. What can you do about it? Easy – give the tree a break and don’t feed it for at least one year. Patience will go a long way in undoing the overfeeding.
Final Thoughts: Why is Your Red Maple Turning Green?
Can you ensure that your red maple has a red canopy every fall? Not quite. Often, it comes down to mother nature, who dictates how sunny the days are and how cool the nights are during the fall.
But you can give your tree a fighting chance by planting it in partial/ full sun, watering it, and feeding it as needed.