How To Prune An Overgrown Japanese Maple

An overgrown Japanese maple can look a bit wild, but with the right approach, you can restore its elegant shape. Learning how to prune an overgrown japanese maple is the key to bringing back its beauty without harming the tree.

It’s a common situation. Maybe you’ve moved into a new home with a neglected tree, or your beloved maple has just grown larger than you anticipated. The good news is that these trees are resilient. With careful, patient pruning over several seasons, you can guide it back to a more manageable and artistic form.

This heading is your main goal. Unlike a light annual trim, rehabilitating an overgrown tree is a multi-year project. Rushing and cutting too much at once is the biggest mistake you can make. Japanese maples are slow growers, and severe pruning can shock them, leading to weak, unattractive growth or even disease.

Essential Tools You’ll Need

Start with clean, sharp tools. This makes cleaner cuts that heal faster and prevents the spread of disease between plants.

Bypass Hand Pruners: For branches up to ½ inch thick.
Bypass Loppers: For branches from ½ inch to about 1½ inches.
Japanese Maple Saw or Pruning Saw: For larger branches. A fine-toothed saw gives a smooth cut.
Rubbing Alcohol or Disinfectant Wipes: To sterilize your tool blades before you start and between cuts if you hit diseased wood.
Safety Glasses: Always protect your eyes.

The Best Time to Prune

Timing is critical for the tree’s health. The absolute best window is late fall after the leaves have dropped, or in late winter when the tree is fully dormant. At this time, the tree’s structure is completely visible, and the sap isn’t flowing heavily. This minimizes stress and reduces the risk of excessive “bleeding” from cuts, which while not usually harmful, can look unsightly.

Avoid pruning in early spring when sap is rising or in late summer/early fall. Pruning too late can encourage new growth that won’t harden off before winter, leading to dieback.

Year 1: The Assessment and Structural Prune

Your first year is about observation and making only the most necessary cuts. Don’t try to fix everything at once.

Stand back and look. Walk around the tree. Identify the main trunk and primary branch structure. Picture the elegant, layered form you want.
Remove the “Three D’s”: Start by cutting out any Dead, Diseased, or Damaged branches. Cut these back to healthy wood or to the branch collar.
Eliminate Crossing/Rubbing Branches: Remove branches that are rubbing against each other, as this creates wounds. Keep the branch with the better form and location.
Address Suckers and Water Sprouts: Remove any thin, vertical shoots growing from the roots (suckers) or straight up from main branches (water sprouts). These are non-productive.
Take out Inward-Growing Branches: Prune branches that grow sharply back toward the center of the tree. This opens up the canopy for better air and light.

After these steps, stop. You’ve done enough for the first season. The tree needs time to recover and for you to see how it responds.

Year 2: Refining the Shape and Canopy

Now you can begin to refine. The goal is to enhance the tree’s natural shape, whether it’s upright (‘Bloodgood’) or weeping (‘Dissectum’).

Thin, Don’t Top: Never “top” a Japanese maple by cutting off the top of the tree or the ends of branches. Instead, practice “thinning.” Remove select secondary branches back to their point of origin on a main branch. This opens the canopy, reduces weight, and allows light to filter through.
Shorten for Proportion: If a branch is excessively long and throws the tree out of balance, you can shorten it. However, always cut it back to a side branch that is at least one-third the diameter of the branch being removed. This is called a “reduction cut” and it directs future growth to that side branch.
Step Back Frequently: After every few cuts, step back and look at the overall shape. Your aim is a balanced, open structure that looks natural.

Year 3 and Beyond: Fine-Tuning and Maintenance

By the third year, your tree should be looking much improved. Now, pruning becomes more about maintenance and subtle refinement.

Continue thinning to prevent the canopy from becoming too dense.
Remove any new crossing or problematic growth that has appeared.
Make small cuts to enhance the silhouette, always following the tree’s innate growth habit.

Remember, you’re an editor, not a dictator. Work with the tree’s existing structure to reveal its best self.

Critical Pruning Techniques to Master

Using the correct cutting method prevents damage and promotes proper healing.

1. The Branch Collar Cut

This is the most important cut for removing entire branches. Look for the slight swelling where the branch meets the trunk or a larger limb—this is the branch collar. Your cut should be just outside this collar, angling slightly away from the trunk. Do not cut flush with the trunk, as this removes the tree’s natural healing zone.

2. Thinning Cuts

As mentioned, this involves removing a branch back to its point of origin. It eliminates the branch entirely without stimulating excessive new growth at the cut site. This is your primary tool for opening the canopy.

3. Reduction Cuts (Heading Cuts)

Use these sparingly. To shorten a branch, cut it back to a lateral side branch that is large enough to assume the terminal role. The side branch should be at least 1/3 the diameter of the branch your removing. Avoid leaving stubs.

What NOT to Do: Common Mistakes

Never Prune More Than 15-20% in One Year: For an overgrown tree, spread the work over 3-4 years. Taking to much off at once is very stressful.
Don’t Use Hedge Trimmers: This butchers the branches, creating many unhealthy small cuts and encouraging a thicket of weak growth.
Avoid “Lion’s Tailing”: This is the bad practice of stripping all inner branches, leaving only a puff of foliage at the ends. It weakens branches and ruins the tree’s form.
Don’t Prune in High Heat or Drought: The tree is already stressed, and pruning adds more stress.
Never Apply Wound Paint: Research shows sealants can trap moisture and hinder the tree’s own compartmentalization process. Let cuts heal naturally in the open air.

Caring for Your Maple After Pruning

After a pruning session, give your tree a little extra care. Water it deeply if the weather is dry, ensuring it goes into its recovery phase well-hydrated. A light layer of compost around the root zone (keeping it away from the trunk) can provide gentle nutrients. Mostly, just let it be and avoid fertilizing heavily, which can force unwanted rapid growth.

FAQ: Your Japanese Maple Pruning Questions Answered

Can I prune a Japanese maple in summer?

It’s not ideal. Light, corrective pruning to remove a few errant branches is okay, but major structural work should be done in dormancy. Summer pruning can lead to sunscald on newly exposed bark and stress the tree.

My tree is very large. Can I still prune it myself?

For very large, mature trees where you need a ladder or chainsaw, it’s safest to hire a certified arborist with experience in Japanese maples. They have the expertise and insurance for high-risk work.

How do I prune a weeping Japanese maple?

The principles are the same, but the goal is to accentuate the graceful, cascading form. Focus on thinning the canopy to prevent heavy mounds of foliage and remove any branches that grow upright instead of weeping. Always prune back to a side branch that points downward.

The branches look tangled. Where do I even start?

Always start with the “Three D’s” (Dead, Diseased, Damaged). This immediately cleans up the tree and makes the remaining structure easier to see. Then tackle crossing branches. These initial steps often reveal the path forward.

Is it to late to start if my tree is already leafing out?

Yes, wait. If buds have broken and leaves are emerging, the tree is no longer dormant. Pruning now will use up energy it has already spent on leaf growth and can cause excess sap loss. Mark your calendar for late fall instead.

Restoring an overgrown Japanese maple is a rewarding journey that requires patience. By spreading the work over several seasons, using the right techniques, and respecting the tree’s natural form, you’ll be rewarded with a healthier, more beautiful centerpiece for your garden. The key is to go slow, make thoughtful cuts, and let the tree guide you.