Japanese maple trees provide a beautiful pop of color to any garden. In the fall, they’re highly sought-after for their delightful red coloring. Fertilizer can help create a healthy growing environment and provide your Japanese maple the nutrients it needs to thrive.
Japanese maple trees grow slowly and are very low maintenance, so fertilizing them is not always necessary. However, if the soil is nutrient-deficient, you’ll need to apply a controlled-release fertilizer with low levels of nitrogen to help support the plant.
The rest of this article will go over how to fertilize Japanese maple trees correctly, why Japanese maples don’t usually need to be fertilized, and what signs you might see that could indicate your tree needs fertilizing. I’ll also share the best fertilizer options for Japanese maple trees and when you should apply them. Let’s get started!
How To Fertilize Your Japanese Maple Trees
Fertilizing Japanese maple trees must be done very carefully. Japanese maples only grow a few inches at a time during each growing season, so they’re very slow growing. This slow-growing speed is perfectly normal for Japanese maples and shouldn’t be rushed.
To achieve the beautiful foliage and coloring expected of a Japanese Maple, it’s important not to disrupt the growing speed. High-nitrogen fertilizers release a lot of nitrogen very quickly into the soil, which can be damaging to Japanese maples. The nitrogen encourages rapid growth, which weakens the plant and creates an unsightly appearance – even causing it to die.
To properly fertilize Japanese maple trees, you’ll need to do the following:
- Choose a mild, slow-release fertilizer.
- Dig holes at equal distances around the tree.
- Place fertilizer granules in each hole.
- Refill the holes with soil.
- Water in the fertilizer.
- Ensure efficient drainage.
Let’s take a closer look at each of these important steps.
1. Choose a Mild, Slow-Release Fertilizer
You should always use a mild, slow-release fertilizer that’s low in nitrogen when fertilizing Japanese maple trees. A typical all-purpose fertilizer is usually rapid-release, meaning all the nutrients contained within the fertilizer are released into the soil at once. This quick surge of nutrients can shock the tree and cause damage to it.
Organic fertilizers are usually preferable to synthetic or chemical compounds when it comes to Japanese maples, as they’re generally slower acting and are more gentle with the roots of the plant.
There are fertilizers made specifically for Japanese maple trees, like this Happy Frog Japanese Maple Organic Fertilizer available on Amazon.com. This type of fertilizer is ideal because of its gentle, low level of nutrients, namely nitrogen.
2. Dig Holes at Equal Distance Around the Tree
Typically, when fertilizing other types of plants, the fertilizer granules only need to be sprinkled onto the soil and watered in. However with Japanese maples, sprinkling the fertilizer onto the ground will cause uneven growth, so a bit of extra care must be taken.
To prepare to apply the fertilizer granules, you’ll need to dig holes in the ground surrounding the base of the tree. These holes should be evenly spaced, about 6 inches (15 cm) deep, and should be located directly between the branch line and the trunk of the tree.
If you have any mulch or compost around the base of your tree, you’ll need to move it to the side before you dig your holes.
3. Measure the Correct Amount of Fertilizer
Before applying the fertilizer, be sure to completely read the manufacturer’s recommendation for the amount of fertilizer to use. These instructions should be pretty straightforward if you purchase a Japanese maple-specific fertilizer. However, if you buy an all-purpose fertilizer, you should apply half of the recommended amount for other types of trees.
You can always add more fertilizer, but you can’t take it away once it’s soaked in, so take special care not to over-fertilize. Similar to rhododendrons, too much fertilizer can cause more harm than good.
4. Place Fertilizer Granules in Each Hole
Once you have dug the holes, it’s time to place the fertilizer. Carefully divide the measured fertilizer and distribute it evenly within each hole. The holes won’t be completely full and may only have a very small amount in each one, but this is perfectly fine. As mentioned before, when it comes to fertilizer on Japanese maples, less is more.
5. Refill the Holes With Soil
Once the fertilizer has been evenly distributed throughout each of the holes, you’ll need to refill the holes with soil. The holes should be entirely filled in and level with the rest of the soil around the base of the tree.
Be sure to fill the holes gently and carefully so as not to disturb the soil or the root system of the tree too much.
If you’ve moved mulch or compost out of the way to dig the holes, you’ll want to replace and level it out after the holes have been filled with soil.
6. Water in the Fertilizer
Now that the fertilizer has been securely deposited into the holes around the tree and recovered with soil, it’s time to water! Water is an essential factor that works to activate the fertilizer. Once the fertilizer has been watered, it’ll begin its slow release of nutrients into the soil and the roots of your Japanese maple.
You should use enough water to moisten the soil and reach the fertilizer, but don’t overdo it. Japanese maples don’t like exposure to excessive amounts of water.
7. Ensure Sufficient Drainage
One of the most essential steps to fertilizing your Japanese maple is to ensure that it has proper drainage. If your tree isn’t irrigated well, it will suffer. Japanese maples like a soil environment that ranges from dry to moist – not wet. If water and fertilizer have nowhere to drain, the result could be a very unhappy maple tree.
Why These Trees Don’t Usually Need Fertilizer
Japanese maple trees don’t often need to be fertilized. Their main requirements for healthy, happy growth are:
- Partial sun exposure: Japanese maple trees like a good amount of sunlight in the morning, followed by a shady afternoon. Any exposure to extremely warm temperatures and direct sunlight can be damaging to the plant.
- Minimal exposure to wind: High gusts of wind or consistently windy weather can cause stress to Japanese maples. It’s best to grow them in a location that’s protected from the wind.
- Well-draining soil: Japanese maples don’t like wet or clay soil. They do much better in healthy, rich soil that drains very well.
- Soil that’s rich in organic matter: A high level of organic matter in your soil is a great way to ensure your nutrients are high and your tree is healthy. That being said, high levels of organic matter can sometimes bring on mushrooms.
If you find mushrooms popping up under your Japanese Maple, check out my other article, for some helpful tips on getting rid of the pesky fungi: Does Fertilizer Get Rid of Mushrooms?
If all of these needs are met, then it’s likely that you’ll never need to fertilize your Japanese maple tree. Because fertilizer has the potential to cause irreparable damage to your tree, it’s best to leave it well enough alone, unless your tree is showing obvious signs of nutrient deficiency. However, I’ll discuss this more in the next section.
Signs That Your Tree Needs To Be Fertilized
Occasionally, Japanese maple trees will exhibit tell-tale signs that indicate they’re experiencing some nutrient deficiencies. Some of these signs could be:
- Discoloration
- Wilting foliage
- Slow or stunted growth
These symptoms typically appear when there’s an apparent nutrient deficiency in the soil or the tree has been planted in an area with excessive sun, heat, or wind exposure. In these cases, you’ll need to use a fertilizer appropriate for Japanese maple trees and gently apply it to help support healthy growth.
Before applying any fertilizer, it’s essential to conduct a soil test on the soil around your tree to determine specific nutrient deficiencies. Because Japanese maple trees have very specific growth needs, it’s critical not to over-fertilize nutrients that are already sufficient.
For example, if your soil test shows a healthy nitrogen level, which Japanese maple trees are very sensitive to, you’ll want to select a fertilizer that doesn’t have nitrogen. Focus on supplementing only the deficiencies.
You should not fertilize your Japanese maple tree if:
- The tree is exhibiting healthy, steady growth
- The tree is in its first growing season
Healthy Japanese maple trees should never be fertilized, as the extra, unnecessary nutrients can be harmful to the healthy, natural growth cycle of these beautiful yet sensitive trees.
Additionally, it’s not recommended to fertilize a Japanese maple tree during its first growing season. During this time, the tree’s roots are too young and weak to be able to absorb the influx of nutrients that fertilizer provides. Fertilizing too early stresses the plant and can cause tree damage or even death.
Waiting until the second growing season will allow the tree the time it needs to establish strong, healthy roots before you fertilize it for the first time. However, you can apply a layer of gentle, organic mulch or compost to help protect it during this critical development period.
The Right Time To Fertilize
If you’ve conducted a soil test, observed your Japanese maple tree, and you have determined that fertilizer is necessary, there are specific seasons that are most ideal for applying the treatment.
The best time to fertilize Japanese maple trees is:
- In the early spring
- After the final freeze of winter
This time of year is ideal for fertilizing most plants and is no different for Japanese maples. Once the final freeze of the cold months has lifted and the frost has melted, it’s safe to apply your fertilizer.
Giving your tree a healthy, controlled supply of fertilizer right before the spring growing season begins will boost the health of the soil and give the plant the nutrients it needs to flourish with a sudden influx of growth.
You shouldn’t need to apply continuing, consistent fertilizer to your Japanese maple tree as you would with other plants. One fertilizer application per year, right before the spring growing season begins, should be more than sufficient to support your tree’s ability to thrive and flourish.
Best Fertilizer Options for Japanese Maples
There are many fertilizer options for Japanese maple trees, both organic and synthetic. Arguably, the best fertilizer type for Japanese maples is an organic one, as their slower distribution of nutrients is more relevant to the slow-growing nature of the tree.
That said, there are plenty of synthetic fertilizer blends out there that are explicitly formulated with Japanese maple trees in mind.
Let’s go over how to use both organic and synthetic fertilizers on your Japanese maple trees.
Using Organic Fertilizer
Organic fertilizer is an excellent option for Japanese maples, coming in many different forms. Some of the most common forms of organic fertilizer recommended for use on Japanese maple trees are:
- Organic compost
- Packaged organic fertilizers
- Wood mulch
Let’s take a closer look at each of these organic fertilizer options.
Organic Compost
Easily home-made with things you already possess, organic compost is one of the easiest and most effective ways to gently fertilize your Japanese maple trees.
Organic compost is made of decomposed food, plant, and animal waste. The materials are broken down over time, creating a nutrient-rich organic matter that’s perfect for working into the soil around your tree.
To apply, you’ll want to work about 2-3 inches (5.08-7.62 cm) of the compost into the soil of the tree. Take care not to dig too deeply into the ground, as you don’t want to disturb the root system of your Japanese maple tree.
Packaged Organic Fertilizer
Many pre-packaged fertilizers formulated specifically for Japanese maple trees are available for purchase. These fertilizers usually have healthy amounts of phosphorus and potassium, with small, gentle amounts of nitrogen.
The manufacturer’s recommendations for the amount of fertilizer to use and the suggested distribution style should be clearly outlined on the package. If you’re using a fertilizer specifically identified for use on Japanese maple trees, you can follow the directions exactly.
However, if you use a more generic maple tree fertilizer, you should only apply half the recommended amount for other types of trees. Japanese maples are sensitive and cannot handle the same amount of fertilizer as different tree types.
Wood Mulch
Wood mulch comprises various organic wood materials like bark, wood chips, or leaves. Wood mulch is a great way to improve the overall aesthetic of your Japanese maple while simultaneously providing protection and essential nutrients to the tree’s roots.
To apply wood mulch, you’ll want to lay an even layer on top of the soil around the base of the trunk, about 2-3 inches (5.08-7.62 cm) thick and wide enough to cover the root system.
Wood mulch application should be done in:
- The spring: To boost nutrients in preparation for the growing season.
- The fall: The boost nutrients and add an extra layer of protection to the roots to aid in the survival of the cold winter months.
Using Synthetic Fertilizer
Synthetic fertilizer isn’t typically recommended for Japanese maple trees because of its quick release and sudden boost of nutrients. However, there are slow-release options that can work well if appropriately chosen.
Typically, fertilizers are identified by three nutrient indicators: nitrogen (N), phosphorus (P), and potassium (K). When selecting a fertilizer for your Japanese maple, you should pay close attention to the N-P-K rating.
The most effective synthetic fertilizers for Japanese maple trees have gentle, low doses of each nutrient. Ideally, you’ll want to see an N-P-K rating of 5 or less for each nutrient (5-5-5 or lower). Anything higher than that will likely be too aggressive for your tree to handle.
Some slow-release options with higher N-P-K ratings can be effective for Japanese maple trees if the dosage is correct. For example, this Osmocote Smart-Release Plant Food Plus Outdoor & Indoor (available on Amazon.com) can be used at a half-dose or less on Japanese maples. This fertilizer is an excellent option because it slowly feeds for up to 6 months, releasing nutrients over time, rather than all in a rush.
Additionally, you’ll need to identify whether the fertilizer is slow-release or quick-release. Quick-release fertilizers immediately inundate the roots with a high number of nutrients, whereas a slow-release fertilizer releases them in a more controlled manner, much more conducive to the needs of a Japanese maple.
Final Thoughts
Japanese maple trees are unique, coveted trees that bring a special pop of color and beauty to any garden. These trees grow slowly and deliberately, creating beautiful leaves and strong roots.
Most often, Japanese maples don’t need fertilizing if planted in an ideal location and have nutrient-rich, well-draining soil. If your plant is struggling, however, you may need to add some gentle fertilizer to help boost the overall condition of your tree.
Fertilizers used on Japanese maple trees should always be low in nitrogen, and organic fertilizers should be used over synthetic options whenever possible.
