By Michael J. McGroarty,
Perry, Ohio 44081 Copyright 2011
People ask about trimming or pruning Japanese maples fairly often and the short answer is yes, you should prune your Japanese maples. Of course, the size and age of your tree, and the type you have determines how you should prune them. When Japanese maples are small, it is absolutely essential that they be pruned for shape and character. There is also some training involved to make sure they develop into the most beautiful specimens imaginable. All of my Japanese maples get pruned and trained at least twice a year.
When Should I prune my Japanese maple?
Really heavy or severe pruning of any plant is best done when the plant is completely dormant. However, that’s not the only time that you can prune Japanese maples. For the most part, I prune mine anytime they need it and that often ends up being the dead of summer. Doesn’t matter, they love it and they respond well to it.
Here’s the problem with pruning at the “Ideal time”. It doesn’t get done. You think your tree needs pruning and you log onto the Internet to find out when it should be pruned. The expert says you should prune them in the early winter or late winter or whatever the expert says. So you say to yourself; “I’d better wait, I don’t want to kill my tree.”
Then come winter it never even crosses your mind. You don’t think about it again until mid spring or the middle of summer. Then you cautiously wait again, and once again miss that window of opportunity. That’s why I am adamant that if something needs pruning, then by all means prune it right now while you’re thinking about it. Unless you are completely cutting a plant down to nothing, it can usually be pruned at about any time of the year.
So what if you cut off some flower buds. A nice plant with a few flowers is better than an ugly plant with lots of flowers. And . . . if you are a diligent pruner your plants will be nice and tight and loaded with blooms and your neighbors will be envious. Gardening is about the end result. How good does it look when you are done with it?
And so it is with Japanese maples. If it needs pruning, then by all means prune it.
Pruning or trimming grafted Japanese Maples
How do you know if your tree is grafted? The great majority of most really nice Japanese maples are grafted, but not all of them. Some are grown on their own roots, so the best thing to do is look for a graft union.
The above photo clearly shows the graft union on this small tree. In this case the graft union is down low, close to the ground, which in most cases is the ideal place to graft a Japanese Maple. However, some are done up higher and you have to look for and beware of that as well. You can see that the rootstock has bark that is green in color and the desired variety has bark that is red in color. It’s important that you locate the graft union on all of your grafted trees because any growth at all coming from below the graft union should be removed. Keep in mind that when a plant is grafted you actually have two different kinds of plants that are pretty much welded together. Of course the “weld” is a natural process that happens when two compatible plants are properly prepared and the cambium layers are lined up.
So watch for any growth that appears on or below the graft union because the leaves on that growth will be very different from the rest of the tree. If allowed to grow those little buds will turn into branches and the branches will grow up through the canopy of your beautiful tree and pretty much destroy it’s appearance. This happens a lot because gardeners don’t realize what it happening to their plant and they are not sure what to do about it.
As you can see in the above photo this graft union is much higher, which means that this tree will put out more growth from below the graft union that will have to be removed on a regular basis. The easiest way to remove that growth is to catch it when it’s still just a tiny bud and just run your thumb up and down the stem and brush those buds right off before they have a chance to produce leaves or a small branch. If you miss that window of opportunity, which is easy to do, you have to remove those little branches with pruners. Cut them all the way back to the stem of the tree so there is no evidence at all that they were ever there.
In the above video I show you exactly what I mean about removing buds from below the graft union as well as good information about training Japanese maples.
Essentially there are two types of Japanese maples and they are pruned and trained differently. There are upright varieties that naturally want to grow in an upright fashion. All new growth grows in an upright direction. Then there are weeping varieties and any and all new growth grows everywhere but upright. If let alone weeping Japanese maples would pretty much just lay on the ground and eventually pile themselves up into a mound. So in order to get a really nice specimen weeping Japanese maple there is both training and trimming that has to take place.
Pruning and Trimming Upright Japanese Maples
So let’s start with the upright varieties. If left alone to grow without any trimming or training an upright tree will grow in an upright direction. However, as it grows it will produce side branches. Some of these will be down low near the ground, or they might be up higher on the tree. It’s your job to decide exactly what you want your tree to look like as soon as you plant it so you can carefully craft it into the tree of your dreams.
All trees as they grow produce leaders. A leader is the main branch that makes up the center of the tree. A typical shade tree and many ornamental trees are grown with a single leader, commonly called single stem. One stem emerging from the ground to a point of four feet, six feet, or even higher before any side branches, or lateral branches are allowed to grow. It is my experience that upright Japanese maples just do not look natural, nor are they as desirable if grown in single stem fashion. I once had a number of upright Japanese red maples that we grew in the field. Most were multi stem, a few we trimmed into single stem trees. The multi stem trees sold much more quickly than the single stem trees.
So it is my belief and personal preference that upright Japanese maples be grown as multi stem trees. How do you make that happen? In some cases the small tree, all by itself will produce multiple branches down low on the tree. In this case your job is to allow these multiple branches to grow, but if there are a number of them you’ll want to select the ones that you think will most likely make for the most interesting and attractive tree and remove the rest while they are still small. Ideally, a multi stemmed tree will have at least three if not four main branches or leaders coming from very close to the ground. In some cases the tree might have a single stem up about twelve to eighteen inches, then the multi stem branches appear. Sometimes you only end up with two leaders, which is fine.
If you have a small tree or a small seedling that is say, eighteen inches tall, you can clip the top of the tree off to stop the pattern of the tree trying to reach for the sky with a single stem. This will slow the tree down, and more than likely buds and eventually branches will appear down low. It’s important to remember that we are dealing with Mother Nature, and at the end of the day she is in charge and sometimes we just have to make the best of what she gives us.
Once you have selected your two, three or four multiple leaders you allow those to grow in an upright direction. They will develop lateral branches as well. Some of these lateral branches you will leave, others you may opt to remove. Keep in mind that as a small tree grows, you want to maintain as many as many leaves on the tree as possible. It’s the leaves that feed the tree as it develops. But in time you’ll want to start removing some of these smaller lateral branches that are appearing down low on your main leaders.
The idea, when the tree is mature, is to be able to see those multi stems, at least up to a height of 30″ or so. Any branch on the tree that you know you’ll eventually want removed should be removed before they reach a diameter of 1/4″. Or the size of a standard wooden pencil.
In the mean time the multiple leaders of your tree are growing in an upright direction. It’s up to you to decide how high you want them to grow. Many people will tell you that you can’t or should not try and maintain the height and size of a Japanese maple. However, it’s your house, your yard, and only you know how much room you have. Not to mention that the prettiest part of these beautiful trees is the foliage and if all of the foliage is way up high you really won’t be able to appreciate it. Every setting is different, and ideally you want to match your tree selection to the setting you have and the amount of room you have. But it reality that doesn’t always happen. You fall in love with a tree and you take it home whether you have the ideal spot for it or not. I do it all the time!
So as your tree matures you carefully craft it into the specimen you desire. Keep removing any low lateral branches that don’t belong and if necessary prune the top of the leaders to maintain the height you want. Eventually you’ll have nice clean multi stems down low and a beautifl canopy of branches up top. You’ll also want to pay attention to the interior of the tree looking for branches that cross, rub or compete with one another. If you find two branches that are rubbing, crossing or competing select the branch you want to keep and remove the other. Keep in mind that any branch growing inside the tree that is never going to find it’s way to any sunlight doesn’t really have a chance of survival so the sooner you remove it the better.
I should also point out that even upright Japanese maples often need staking when small. That’s only if they are drooping over or just not growing straight up.
This above video will give you a visual of what I am trying to explain here.
Pruning and Trimming Weeping Japanese Maples
All of the Japanese maples in the world, the Red, Weeping, Lace-leaf varieties are probably the most popular and the most sought after. That’s because they are beautiful and special in a way that you really can’t describe. But if left untrimmed and untrained they can get kind of ugly, and we don’t want that to happen to such a special plant. So I will explain just exactly how and why you should trim and train these weeping varieties.
But first, I’d like to point out that the selection of weeping Japanese maples is much greater than most people realize. There are green varieties and there are a number of different variegated varieties. So don’t limit your options! Here at Japanese Maple Lovers it is our goal to introduce you to all of these incredible and fascinating plants. Enjoy!
Have you ever wondered, or asked yourself; “Why are these tree so doggone expensive?” Two reasons. They are relatively slow growing and they are not the easiest plant in the world to grow. It takes time, effort and knowledge to produce a really nice lace-leaf weeping Japanese maple. Here at Japanese Maple Lovers my goal is to give you the opportunity to purchase these plants at small sizes, and at deeply discounted prices. But when you do that, it will be up to you to prune and train these Japanese Maples into beautiful specimens. You can do it! With a little education. But once you master this art you will so much more appreciate the trees in your yard because you will have had so much involvement with their up bringing. Sound familiar? Don’t worry, they won’t ask to borrow money once you have them raised!
The above photo is Acer palmatum dissectum, ‘Crimson Queen’. So that’s out goal right? To end up with a beautiful tree like this one.
However, what we often start with is a plant like this, or worse yet a plant like the photos of the graft unions at the top of this page. So let the work begin! The plant is this photo does not look happy at all, but that’s because this photo was taken in November after a frost or two. So some of the leaves were damaged and others not. Also, when I received this tree it had not been trained at all, and it was allowed to grow for probably two seasons with no training. That makes my job of getting it to look like I want more difficult, but not impossible.
As mentioned earlier the weeping varieties truly have no upright habit to them at all. They’d prefer to just lay on the ground and spread out as they grow. Unless you have a wall that the tree can creep over and hang down or some kind of a Japanese garden setting that’s probably not at all what you want. So the very first thing you need to do is figure out how you are going to get some height out of your tree. Typically, if you can get at least one main branch up to a height of 42″ or so, that would be ideal. From there you can allow the lateral branches to develop and eventually form a really nice head.
So the very first thing you need to do is put a stake in the ground next to your tree. The plastic stakes that you can get at the garden stores is fine. Then you have to find a branch that you can tie to the stake that will be your main leader. In the above photo you can see that I’ve tied a number, or a bunch of branches to the stake. Coming out of that bunch of branches I’ve got a main leader that will eventually make up the main stem of my tree. More than likely, over time, many of those lower branches will be removed because eventually I want a weeping canopy that will completely cover that part of the tree. The weeping canopy will eventually block all sunlight to that area and those branches won’t be able to survive any way. But for now they get to stay because they are helping to feed the tree through photosynthesis.
So the goal is to train at least one branch upright to a height of about 42″ and then start training all of the lateral branches to form that weeping canopy. Even though you eventually want a canopy that is say, 40″ wide, you don’t want to allow those lateral branches to grow out to that distance without trimming them at all. The more you prune them, at least a few inches off the tip of the branch, the more lateral branches they produce, and it’s that maze of lateral branches that make up the head of the canopy.
Every Time you prune a lateral branch you get more lateral branches from that branch. Each of those lateral branches will in turn produce more lateral branches. So don’t get impatient or worse yet, don’t be afraid to prune the tips of of those lateral branches. There’s nothing you can do to speed the process of trying to develop a nice head on your tree. It takes time, and it takes regular pruning.
And at this time I need to make a big announcement.
Japanese Maples do not like fertilizer!
They cannot process or use much commercial fertilizer at all. So no fertilizer is better than too much. Fertilizer will not make your Japanese maple grower faster. It can and will kill your tree. Japanese Maples like good rich soil that contains a lot of well composted organic matter that drains well. Two things that Japanese maples really don’t like. One is fertilizer, the other is too much water or being planted too deeply.
Think about the weeping canopy part of the tree as a snow ball. A snowball builds one layer at a time as it is rolled around in the snow. And as the saying goes; “The bigger a snowball gets, the faster it gets big.” Same thing for your weeping Japanese maple. You have to allow it form one layer at time. Each layer will produce a bigger, more intricate layer until you have a nice big, beautiful weeping canopy on your tree.
However, most people don’t know that and they are afraid to death to cut anything at all off their Japanese maples. That’s a big mistake and I want you to know better than that. A lace leaf weeping Japanese maple that is staked upright at the nursery, then taken home by it’s new owner and left untrimmed starts to look like an old fashion TV antenna.
The above photo is a lace leaf weeping Japanese maple that purchased from a wholesale grower. They did a good job of getting it staked upright from the very beginning, but now it has grown quite one sided. I’m assuming that’s because they were probably packed tightly together in the nursery and it just didn’t have enough room or adequate sunlight to develop on the side that is lacking branches. For me this is an easy fix. This winter I will go through the field and cut those lateral branches back to about half of what they are now.
If I don’t cut those branches back to about 50% next spring they will put on all kinds of new growth, but most of it will be way out at the extreme ends of the branches making the tree even more one sided. I don’t want the tree spending all of it’s energy putting on branches where I don’t want new branches. I need to get this tree tightened up so as the weak side starts to develop new growth the stronger side will grow pretty much in proportion to the rest of the tree.
So training your weeping Japanese maple is a process and it’s a process that you really should do each and every year to make certain that your tree or trees just getting better and better.
Pruning a Mature Lace Leaf Weeping Japanese Maple
So now let’s assume that you have a fairly mature weeping Japanese maple in your yard that really hasn’t been pruned, or hasn’t been pruned properly.
1. Examine the tree. Look for leaves or branches that look like they just don’t belong. If your tree is of the dissectum family and has delicately cut leaves, all of the leaves on the tree should pretty much look the same. If they don’t, then that’s a good sign that you have a branch or branches that have grown from below the graft union. Those entire branches should be removed before you do anything else.
2. Go around the tree with pruning shears and remove any branches that are touching the ground, or are too close to the ground. How far up from the ground your tree should be is a personal preference, but I’d say that ideally you don’t want anything closer to 12″ to the ground. That distance will allow for new growth that still will not touch the ground.
3. Stand back and look at your tree. Ideally I think these trees should be shaped like an umbrella, or maybe a mushroom. High in the center then slowly tapering down as you get away from the center of the tree. Standing back and looking at your tree, picture that shape in your mind. Mentally draw an imaginary line with your eyes and pay attention to only what is inside of that imaginary line. Everything outside of the imaginary line should be removed.
4. It’s as simple as that. Everything outside of the imaginary line should be removed. If you do that each and every year your tree or trees will be beautiful.