Instead of just cutting the top of your Japanese maple off, you should learn how to prune the crown of the tree. Properly pruning a tree not only diminishes its height (if done correctly) but allows for a healthier tree.
Japanese maples absolutely need pruning.
Pruning and knowing how to fix common issues – such as a Japanese maple that has grown too tall – are extremely important for the health of the tree and the aesthetics of your landscape.
What Is the Proper Method to Prune a Japanese Maple that is Too Tall?
Japanese maples come in laceleaf forms and upright, or mounded references.
The laceleaf varieties would be better compared to the structure of a weeping willow, which grow long, spindly branches that will soften with a heavy rain and assume a vertical position. An upright Japanese maple is more rigid and stands tall, comparable to an apple or Bradford pear tree.
Both varieties are more than capable of getting too tall for their environment, especially when they are not pruned every year.
Their desired size and shape should be managed progressively, not in one sitting or season.
Don’t: Chop the Top of the Tree Off
There is a term referred to as topping. Topping is an obsolete technique that is still not well understood today. The only time you would top a tree is when all else has failed.
Cutting off the top of an upright Japanese maple will find it probably ruined for its life, either due to infection or completed decay at the sight of a large gaping pruning wound.
Do: Conservative Crown Reduction
Crown reduction is one of the best strategies to reduce height on a Japanese maple in that it only removes branches that are growing the wrong way or rub other branches.
This not only enhances the tree’s appearance but limits excessive height.
Do: Reduce Size of the Entire Tree
If your Japanese maple is extremely overgrown, you want to reduce it not only in height but width and fullness.
This conservative approach yields the best natural pruning results and allows your tree to grow healthy and strong for years to come.
To reduce the entire size of the tree, you want to:
- Prune bottom branches to shorted length
- Work upward
And, as you work upward, you will shorten the limbs, taking more away from the limbs higher in the tree and not as much lower down.
This is particularly effective with upright Japanese maple trees, as they have more rigid limbs.
Be warned! Modify your conservative approach to the bottom that if you remove too much you will disconnectatively remove a major limb, as you progress up the tree.
A laceleaf maple would need the same tapering method as a upright maple, causing only to remove more from the top limbs as compared to the bottom limbs.
Keep in mind: this pruning style is a little more forgiving with this type of tree, it just entails different angles making mistakes less easy to see since the limbs are positioned at different angles.
When Do I Prune My Japanese Maple?
The best time to prune for height or volume is Winter, followed by Summer. In Winter, the trees have fewer leaves and make it easier to see the overall structure of the trees and easily determine which branches to cut so it retains its shape.
You may see undesirable growth during Spring, but this is not a good time to prune, the trees are producing delicate new growth and sap.
Arguments against Fall are typically, because it is the time of year most trees and plants are exposed to infections and fungi followed by Winter when they are exposed to cold and frost.
Avoid This: NEVER prune Japanese maples when the temperature is over 80 degrees F, any season.
Are There Any Special Considerations When Pruning Japanese Maple Trees?
There are a few things to know about a Japanese maple before you attempt to prune one yourself, here are several tips for the preservation of your tree.
Japanese Maples Do Not Tolerate Heavy Pruning
This means your desired shape may take years to attain.
Japanese maples need to be pruned at a very young age to avoid producing small, whip-like branches which will create some weakness and unhealthiness in the tree.
Light and yearly pruning will allow you most years to maintain the desired height for your tree without drastic action.
Do you want a tree that is natural in size looks or is pruned?
If you prune aggressively, you may end up with a tree that has small branches on top and long, drooping branches at the bottom.
This will not be noticeable when the tree is full of leafs, but it certainly will be in the Winter.
The difference does not bother most for the intent of keeping the tree at a certain height.
Japanese Maples are Slow in Growth
These trees grow at 1-2 feet a year.
This means that any over-pruning or pruning blunders will take a very long time to correct, so do not do anything to your tree unless you are ready to live with that decision.
In conclusion
As with most things, it is more effective to prevent large trimming to a tree that is very sensitive.
Otherwise, there is a method that, if done properly, will safely and effectively minimize the height of the tree.