How to Prune A Japanese Maple
In this Episode of the MrMaple Show, Tim and Matt talk about how to prune your Japanese Maple. They will be talking about why you should prune it, when you should prune it, and some tips so that you can gain more confidence while pruning your Japanese Maples.
Why would you prune a Japanese Maple?
One of the main reasons you would want to prune a Japanese Maple is to increase vigor. Pruning pushes a lot of new growth, and it helps the roots to begin expanding and establishing in the ground. If you want your plant to put on a lot of new growth, pruning is a great way to do that.
When should I prune my Japanese Maple?
There are a lot of different opinions on when you should prune, but we will go over what works for us. These are some things that have given us success in pruning Japanese Maples, as well as reasons why and how.
Buddy Lee made a good point when he said that you only want to prune (deciduous) plants at times when you could fertilize, and that is a great point because you will create an immediate growth response to pruning. Pruning flushes, which is something that you only want to do in times when you'd like to activate growth, which is why we don't recommend pruning in the fall. We don't want new flushes of growth going into winter.
We prefer early spring, somewhere around mid-late March. We are located in Western North Carolina, so we do get a little bleed out during this time frame, but it seals much quicker (7 days versus 3 weeks during other times of the year). Pruning your Japanese Maple during the spring will cut down on the time where the tree has open wounds since the tree is at its most rejuvenative stage. A lot of people are concerned about the bleed out on the trees, but pruning does not hurt the tree. Spring is the time when the tree will heal the quickest.
Pruning during the early March time frame is going to increase energy in your plant, as well as increasing the root ball and secondary flush (the tree will leaf out with a huge push). Another reason that we recommend pruning during this time frame is because there are not yet leaves on the tree, so you can see the branches and structure of the tree so much better. It is easier to get down in the tree to prune.
You can certainly prune in other times of the year, but these are the things that we have seen to give you the best success. It's a nurseryman trick to prune in the early spring since the immediate flush will create the best new growth as well as the most vibrant colors, increasing the overall health of your tree as well. Pruning in the summer will decrease the growth and vigor of your tree, while pruning in the fall can leave openings in your trees for bugs.
Some people like pruning during the late summer as a bonsai method to reduce the overall growth of a tree. You can do this in container or landscape, typically to increase vigor and to have a lot more branching from the pruning. Pruning in the late summer after the flushes have hardened off will reduce the overall size of the tree, so you're taking energy away from the plant.
Reasons you should prune your Japanese Maple
Reason 1: To increase vigor in your Japanese Maple.
One thing to keep in mind is that pruning is good for the health of the plant. It's one of those things that people don't do enough of. When you begin seeing a lot of twiggy growth, that is when the plants are starting to slow down quite a bit in growth. If you prune a Japanese Maple, it encourages a lot of growth, so it's a great thing to do to help the plant have vigor and keep growing to make a beautiful tree out in the landscape and/or garden.
Reason 2: To remove branches that are not aesthetically pleasing.
Pruning is something that can become an art form. People prune their Japanese Maples and shape them into beautiful masterpieces.
Reason 3: To remove dead wood.
This can include dieback and dead or crunchy parts due to frost, cold snaps, or other underlying issues.
What tools should I use to prune my Japanese Maple?
Joshua Roth Bonsai Pruners
One of the pruners that Tim and Matt use are concave bonsai pruners, typically Joshua Roth, although sometimes you can find cheaper brands that will work pretty good. These are stainless steel concave pruners used in bonsai, but you can make very detailed and intricate cuts with these.
You want to be conscious that you do not cut anything big with these, since you will break the pruner. We recommend not cutting anything over the thickness of a pencil, as you do not want to waste your money.
The pass-throughs are good for cutting something a little bit larger that does not need to be as intricate. If you start cutting anything bigger than your pinky, you will want to bring out a saw, and make sure that it is sharp.
Rubbing Alcohol & Paper Towels
One of the most important tools that people often forget about is rubbing alcohol and a towel. We recommend paper towels as we wet the towel with rubbing alcohol. Some people prefer a bleach solution, but we find rubbing alcohol to be much easier to find, as well as not having the risk of bleaching your clothes as you are pruning throughout your garden.
The key thing to think about is: "What am I pruning?" A lot of times, you may be pruning dead growth in plants all around your yard with your saws and pruners, and you need to make sure to keep those tools clean. The dead growth may be dead because something is wrong with it, and you do not want to spread that from tree to tree as you go through your yard. When you prune, you are making surgical cuts, which means you want to be as clean as possible during this entire time. It's really important to clean your tools before you start this, and to clean them during and after as well, just to make sure that you aren't spreading anything. If you're cutting out dead wood, it could be dead for another reason besides a late frost/cold snap, it could be bacteria or dieback.
We recommend cleaning your pruners between each tree, so after you are finished with one tree you should clean your pruners, then go on to the next tree.
How much can I prune from a Japanese Maple at one time?
This answer varies a bit, as during the spring you do not want to prune out more than 40% of the Japanese Maple. During the summer, it's even less.
If you want to do more and more work on your tree, remember that it's not just one year that you can prune. You can prune this year, make some major adjustments, then prune next year at the same time of the year with more major adjustments. If you have minor adjustments that you want to make, you can do that during the summer, but remember that you are typically reducing growth when you prune during the summer.
Don't be afraid to prune Japanese Maples, just make sure that you remember the key basics and have them in place so that you are going to have the best success rate. The good thing about nature is that it regrows just like a haircut. You certainly want to be careful about how you go about pruning, but it's very easy to do.
What should I prune off of my Japanese Maple?
The first thing to look for when pruning a Japanese Maple is the dead or damaged growth. It's not uncommon for Japanese Maples to have a bit of twig dieback, especially in the Zone 5 and 6 environments. (Here at MrMaple, our winters are conducive to have a little bit of twig dieback, which is something that is not typically super damaging on a mature plant.) If you see something that is already dried or has crunchy bark, don't be afraid to go ahead and remove that. You can actually remove dried or crunchy growth at any time of the year due to it already being dead and robbing the tree of energy. It will improve the overall health and look of the tree.
Key Factors in Determining What to Prune
First and foremost, you want to keep in mind what your cultivar is supposed to look like. You aren't going to prune an Inaba Shidare to look like a Seiryu, you would be in a losing battle. Our website gives lots of information about the different cultivars we offer.
When you prune a Japanese Maple, you are enhancing the traits that the cultivar already has, so you don't want to have to reinvent the wheel. Pick what the cultivar is and try to accentuate the natural growth rate of that cultivar to make it better.
Taking Out Twig Year Growth
Taking out twig year growth will push a ton of growth and energy into your plant. One key piece of advice is to let your plant grow before you trim it. Don't be too rushed to get into pruning it, as we here at MrMaple.com do not prune any Japanese Maples until they're past a 7 gallon size, and that's because we want to let the natural growth rate of that cultivar take over. We want our uprights to look like uprights; we do not want them to be round balls. We do not recommend pruning 1 gallons, 2 gallons, or even 3 gallons. You can start to play with the shape a little bit, but you will want to let the natural beauty develop because we cannot beat nature.
The only things you will want to prune on a younger plant is a central leader and developing a second leader.
One of the easiest ways to get vigor in the spring garden is cutting out twiggy growth. Twiggy growth tends to rob Japanese Maples of their new growth flushes, and by taking some of that, you can really increase the overall growth rate. When we talk about twiggy growth, we are talking about the smaller, thinner growth. Whenever you have growth from the thicker branching, you actually get more growth overall from the plant and the xylem flow, which is how the plant takes water and nutrients, and is more efficient in the branching. When you prune twiggy growth, you will get more growth overall for the plant and it will make a much larger tree much quicker.
Branches that are going to be rubbing or touching long term are considered conflicting branches. You may want to take these out to create a more open aesthetic for your Japanese Maple. Sometimes it can be more desirable to be able to see the whole structure, so by taking out branches that are growing back toward the bae of the plant, you can create a better looking plant.
Choose the branch that you like better, one you think that you can develop to make your tree better; take out the ones you don't like, and that will give you a more open aesthetic. In Japan, their open aesthetic is based on how the sunlight hits the branches, which is a more natural style of pruning.
A good wat to avoid conflicting branches is to go ahead and preemptively remove branches that are headed back toward the interior of the plant, so you can find branches that you know are going to head back toward the base and remove those. By doing that, you're going to open up the structure of the plant and you're going to be able to see into the plant a bit better.
Often when pruning a Japanese Maple, you have to make a choice on where the central leader is going to be. Taking out the central leader can make a tree smaller. You want to keep your central leader as your uppermost point in an established plant so that you create a focal point. Be conscious of letting the tree grow for a while to determine its own central leader before forcing one. Sometimes another one will still become dominant and you'll end up with a side branch that becomes way larger than the rest.
Don't be worried on a 1 gallon plant if you prune out a central leader or somehow the top snaps off during shipping. Japanese Maples have a dominant central leader that they develop naturally, and sometimes nurserymen will go in and prune out the top of a Japanese Maple to get it to flush a lot of growth sideways. That's not going to affect the overall shape, it will just give you more branching.
Branches That You Don't Like
The next step is to take out the branches that you do not like. It's impossible to prune someone else's tree because you may not like a branch while the other person thinks it's an amazing one. You can't really finish someone's painting, so it's like artwork at this stage. It's a good time to go ahead and take out any branches that are bugging you or are not desirable to you. Basically, you will take the branch away which tells the tree "Hey, let's put all the energy in the part I like about this plant and take it away from the part I don't like." Don't be afraid to take out those bad branches.
Take out the branches you don't like because they will only get bigger. Leave the branches that you like and develop the shapes that you want to develop with those trees.
Quick Pro Tip for Pruning Japanese Maples
If you're pruning off the underside of the branching, you can often hide those cuts. If you're in a garden that you want to hide those cuts, pruning on the lower side of the branching is a great way to remove the branching. If you're deciding between two branches, often picking the branch that's coming out from behind, from the lower part, will give you a better overall aesthetic.
Another thing to be conscious of when you're pruning in the early spring is that you are pruning for the new growth flush, so the tree may not necessarily look completely finished when you are done pruning.
Additional tags: Pruning Japanese Maples, How to Prune a Japanese Maple, MrMaple.com, MrMaple Show, Buy Japanese Maple Trees at MrMaple.com