Pruning is a beneficial practice for enhancing the natural beauty and promoting the long-term health of Japanese maple trees.
Making strategic cuts here and there may seem scary, but once you know how, it quickly becomes a very simple and worthwhile practice.
If you don’t know where to start when it comes to tree pruning, don’t sweat it — we’re here to guide you step by step through the pruning process and provide a rundown of the Dos and Don’ts of pruning a Japanese maple, FAQs, and more.
- Heavy-duty gardening gloves
- Hand pruners
- Pruning saw
- 70-90% rubbing alcohol
- Clean towel/microfiber cloth
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Why Prune Japanese Maple Trees?
Japanese maple trees need pruning not only to maintain their health but also the original aesthetic. Tackling excess growth and removing clutter helps keep the canopy open and airy, preventing the likelihood of disease.
Pruning your tree can also reduce its weight if it is too heavy on the top or one side.
When done right, it can also help direct the structure and overall habit of the tree, helping your Japanese maple sustain its natural form whether it is rounded, weeping, or vase-shaped.
When Should a Japanese Maple Be Pruned?
If you’re planning to make structural cuts (i.e., pruning large branches), then winter is generally the best time to do so.
Not only is the tree in its dormant stage, meaning severe cuts will cause less stress, but you can also see the canopy shaping more clearly without the foliage.
Should you need to remove a broken branch after a storm or spot a dead branch (lighter gray, budless) or diseased growth on your maple, these sections can be pruned any time of year.
Japanese Maple Pruning Guidelines
Remember that structural, large-scale pruning should always be done during the tree’s dormant months (late November to January) and that any finer pruning and trimming should be left until spring.
You should also try to make sure that your cuts are made as close to the collar of the branch as possible as cuts made in the collar itself may not heal.
Another essential aspect of properly pruning your Japanese maple is to always use the right tools.
Master gardener and arboretum curator Les Engels advises the use of hand pruning shears for branches up to ¼ inch in diameter, loppers or heavy-duty shears for branches up to 2 inches in diameter, and a pruning saw for those larger than 2 inches.
Don’t forget to sharpen your tools when necessary as blunt tools are more likely to snap branches!
Let Young Trees Mature Before Pruning
While they’re still developing, young Japanese maples can send out whippy side branches. These should not be removed as pruning these off will only encourage further whippy branches!
Allow young trees to mature before getting the pruning shears out as you want to wait to see the branches widen and become sturdier (this may take 8-10 years depending on the type of Japanese maple tree).
Branches That Should Always Be Removed
A helpful way to remember which branches to remove is to think “DDD” — the dead, the damaged, and the diseased branches.
An amendment to this rule is if a branch is touching your home, another building, or obstructing a walkway.
What Not To Do When Pruning a Japanese Maple
Jackson’s Nurseries shares some of the big no-nos of pruning your Japanese maple tree:
- Never prune more than 1/3 of living tree material each year.
- Don’t cut branches that are more than half the diameter of the main stem.
- Don’t remove more than ¼ of the foliage from one branch.
- Never remove more than 20% of the crown. This not only stresses the tree but also encourages unsightly growth in its place.
How To Prune a Japanese Maple
Now it’s time to get started. Here’s what to do:
1. Consider Tree’s Natural Shape Before Starting
This is important if you are trimming for aesthetic purposes rather than to remove broken, dead, or diseased branches.
Find out what Japanese maple variety you have and remember to prune only to accentuate its natural form (vase, oval, pyramid, etc.).
Stand back to see if any interior branches are detracting from the natural form and decide which cuts to make.
2. Determine the Cut Size To Choose the Right Tools
Will you be pruning branches no wider than your pinky finger (hand pruning shears), or will you be pruning branches a little wider (loppers and pruning saws for larger branches)?
It’s likely you’ll only need a pruning saw when making larger structural cuts in winter, so make sure you’re using the right tools for the pruning job.
3. Sanitize Pruning Tools & Don Protective Gear
Clean any pruning tools you plan to use by sanitizing them in a solution of 90% alcohol or a solution of 9 parts bleach and one part water. Soak for 20-30 minutes.
Put on some heavy-duty gardening gloves, and rinse tools in cool water before wiping dry with an old (clean) towel or microfiber cloth.
4. Using Hand Shears, Trim Limbs at Base of Tree at a 45° Angle
If you prefer an elevated look to your maple (visible trunk with foliage kept to the middle and top), remove lower limbs or suckers growing from the base of the tree.
Taking your hand pruners, position them parallel to the tree and snip off the desired branch just above the branch collar, cutting at a 45-degree angle to prevent disease.
5. Identify Any Crossing Branches in the Canopy
Inspect the tree interior for any branches that may be crossing/overlapping each other closely to the point they are rubbing together as this can cause damage in addition to creating a crowded or unkempt canopy.
Depending on where the crossing is taking place and the diameter of the branch(es), make a 45-degree-angle cut just above a branch collar using either your hand shears or lopper tool.
6. Repeat for Dead, Damaged, or Diseased Branches
Identify any broken branches hanging down or ones that are dead (these will appear lighter gray compared to healthy growth and have no buds on them).
Diseased branches will have discolored bark (rusty brown/black patches), cracks, or sticky substances oozing from cracks.
Additionally, look out for any other branches that seem out of place with your tree’s natural habit in the tree’s interior (i.e., branches growing in a bolt-upright direction on a pyramid-shaped maple or branches growing out to the side on a weeping tree).
Making Structural Cuts in Winter on Large Trees
Using a pruning saw, you can easily make cuts to larger, thicker branches on bigger Japanese maple varieties using the 3-cut method:
- First, make a cut on the underside of the branch, positioning your cut roughly 6 inches away from the main stem. When making the undercut, don’t cut all the way through — leave about a third of the branch intact.
- Next, make a second cut at the top, about an inch out from the first cut you just made.
- Finally, with the main part of the branch removed, cut off the stump at a 45-degree angle, taking care to cut as close to the branch collar as possible.
Frequently Asked Questions
Can You Prune a Japanese Maple To Keep It Small?
Japanese maple trees with an upright habit can be kept small by pruning the central leader (the main trunk in or near the middle) while the tree is in its juvenile stage.
Making this cut while the tree is still young can reduce height by pushing growth out to the side instead of shooting straight up.
Can You Cut the Top Off a Japanese Maple?
Cutting the top of a Japanese maple is not recommended as this can cause stress to the tree and stimulate new and unsightly, scraggly growth at the crown.
You should only carefully thin the topmost portion of the crown, and never remove more than 20% of the crown’s density.
Can You Trim a Japanese Maple in the Summer?
Yes, trimming is encouraged in late summer if your goal is to stunt the growth of your Japanese maple tree.
Removing growth before it begins hardening for fall and winter will remove some of the tree’s energy reserves for the following season, resulting in a more manageable tree over time.
Can a Japanese Maple Be Trimmed in the Fall?
Yes, fall can be appropriate for trimming your Japanese maple as the tree has begun to harden in preparation for winter dormancy.
For heavy pruning that can wait, such as aesthetic shaping, it is advisable to make these cuts later in the season (late November to January) when the tree is dormant.
Should I Thin Out Japanese Maple?
If the canopy appears crowded, you can make necessary cuts to improve the overall shape. Thinning is best done during the winter when you can judge the right amount to trim.
However, over-thinning your Japanese maple can risk inviting sunscald to the thin, tender bark.
How Old Should a Japanese Maple Be Before Pruning?
In the first 2-3 years after planting, broken and dead branches can be removed, but regular pruning to control shape won’t be necessary until the tree is much more mature (about 10 years old).
Japanese maples are best left unpruned for as long as possible to achieve a strong frame.
How Should My Japanese Maple Look?
There are two main types of Japanese maple trees: upright and weeping.
If your maple tree is upright, dissimilar leaves and branches growing in a different direction from the canopy should be removed.
If you have a weeping maple, excess growth should be removed from the base to help maintain a neat umbrella shape.
Pruning this elegant tree species for the first time can be daunting, but you’ll know you’ve done it right when your Japanese maple is showing signs of more vigorous growth in season and the foliage is coming in at the expected time with vibrant (not dull) coloring.
When pruned correctly, the tree’s natural shaping should be intact with all limbs growing in the right direction to maintain its upright or weeping habit.
Depending on the pruning job (trimming a few suckers or removing several broken/dead branches, making structural cuts, etc.), pruning your Japanese maple should take 20 minutes to an hour. Don’t be afraid to take your time.
We hope this guide helps!
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