Dont' Be Afraid to Prune Those Japanese Maples

…they are not nearly as fragile as you think!

These dainty looking little trees are tough as nails, really. These little pieces of sculpture are so cute and small that when placed in the landscape they often outgrow their allotted space and become monsters, and you know what happens then; we end up pruning them out of the way rather than pruning them the way they want to be.

The emphasized part of that last sentence is biological and a truism. The way any tree wants to be is nothing more that genetic hardwiring that must be respected. If not, our new, cute little tree is going to take us to task and win every time. So what can we do to help these gorgeous Picasso’s on their way to adulthood? Let’s take a look.

  • Japanese maples can be pruned anytime of the year. If I were to pick the best time, it would be winter, and winter depends upon where you live. So let’s say the dormant season. In the Mid-Atlantic, that occurs between Thanksgiving and Easter, sometimes. Nothing in Zone 7 is cast in stone; transition zones can be confusing! While we are on the subject of timing I will say that I try not to prune my trees when they are actively growing or dropping leaves. This is an important time for trees that requires a great deal of energy, and I’ll leave it at that. Of course, the dormant season is the best time to prune most deciduous trees for myriad reasons; no bugs, fewer disease pathogens, no leaves to rake but most importantly, a Japanese Maple’s branching pattern is visible and that’s one of the keys to pruning them. When you have finished pruning your Japanese maple you often want to see the tree’s branch structure through it’s curtain of leaves, which leads to the next pruning suggestion.
  • Try not to nit pic your tree when pruning. I have spent a great deal of my life making too many pruning cuts. That does not mean I removed to many leaves and branches, it means I spent too much time making too many cuts that could have been made by removing a larger piece of wood. Did that make sense? I was nit picking the tree to death with my hand pruners when I should have been making a larger cut with my handsaw. I was cutting branches back when I should have been taking off the entire limb. The results of this technique can be striking. A tree should have holes or gaps in its branching design. Look at your Japanese maple by walking around and around and around the tree. Look at it carefully. This is a bit off the subject but try this trick at night. It can be applied to your diurnal pruning. Go outside on a clear night and look up into the stars. Look directly at one star, directly at it. It’s difficult to see the star you are staring at. Now, look a little to the left or right, just barely and the star comes into focus. Why? I have no idea! It just does. Tomorrow, when it’s light go out and do the same thing with your Japanese maple and you will begin to see things that do not conform to the general characteristics of the tree. Take the tree out of focus then back in. The things your eyes pick up will be larger pieces of wood that are out of place, which is why your eyes pick them up. Cut them out, and use common sense not to take too large of a limb. Why have two limbs doing the job one. The moral of the story: Take out the greatest amount of wood with the fewest cuts possible. Again, use common sense. Actually, proper biological pruning takes a great deal of common sense.
  • Prune out all deadwood. The small dead will break out with ease by simply brushing your hand across dead twigs. As the tree grows and becomes dense, interior branches become shaded and die, creating a situation that we can affect by cleaning and thinning the crown. This type of pruning has biological and artful advantages for both pruner and tree. Our pruning will have a lasting affect and has everything to do with our tree’s future health and longevity. We can now become our tree’s best friend as long as we follow the physiological requirements the tree has set up for us to follow. How trees grow and how they set up reaction and barrier zones to wounding is a road map for us to follow as we take our trees on the road to great health. The art part will follow; trust me.
  • You can generally remove a great deal of wood from your Japanese maple and depending on its health, mass and condition, never more than half of its total mass. Watch the Japanese pruning masters and you will be aghast. A good rule to follow is that as your Japanese maple ages, the less able it is to deal with wounds. The wound reaction process is extremely complicated in woody plants and as trees age they lose the ability to stimulate wound closure efficiently. This means you can still make many cuts, (all cuts are wounds); just make smaller wounds, (cuts). Begin to prune your maple to give each branch its own space, knowing that some spaces will be small and others larger with openings between and amongst them. Prune to see your tree’s branch design by removing branches that block the view to a handsome twist or turn in direction. You may not want your maple to be transparent while a shimmering translucency may be exquisite. Impressionist painters kept many of their works out of focus, making you look deep into rather than at their masterpieces. Japanese maples graft branches beautifully, forming circles and shapes a single branch cannot achieve. Stop, look at your canvas, listen to what it is trying to say. Look at your tree from inside and out. Sit beneath or stare from far away. Let it hang over the sidewalk making visitors to your gallery surrender the right of way to the rightful owner. I have clients that have redesigned an existing walk for the sake of their tree’s artful well being. In fact, I have a client that has cut the fascia board and soffets from their house to allow a giant white oak to grow unobstructed! Now that’s tree preservation. (Yes, we check the tree’s stability every year to be sure it can remain in its space safely!)
  • Exactly what you prune out of your Japanese maple will depend upon the variety of tree you have. Let’s break them into two categories, upright or dissected and weeping. Your upright is usually larger and more “tree” like. Actually, these maples can get quite large and need a great deal of room. This type, such as bloodgood is usually planted in the middle of the front yard or if you are using a smaller upright variety such as coral bark you can use them closer to walks and structures. Clean and thin these as you would other ornamental trees by removing deadwood, conflicting and interfering branches. These branch structures are easier to see due to their upright habits. On the other hand, dissected varieties resemble one of the “The Munsters” family members affectionately known to all of us as “Cousin It”. (I have heard this exact description from people more that once!) Few people are comfortable pruning this type of Japanese maple simply because they have no idea where to begin. I’m afraid too many of these types look as though they have just been to the barber. To the seasoned eye however, each one is an opportunity to create, and any arborist worth their salt would fight for the right to perform such a pruning task.
  • THE DISSECTED JAPANESE MAPLE: This type of Japanese maple should not be left unattended. They will outgrow their good health, becoming so dense that interior growth begins to die. This is not only unattractive but opens the tree to opportunistic disease pathogens, as well. Japanese maples crave sunlight on all of their parts, which is an excellent key to pruning. This is not to say that Japanese maples will not grow in shade. They grow well in shade and will mature in a more open fashion. As you begin to open the tree you will begin to see light filtering through the canopy. It doesn’t have to be much, just enough to showcase what needs to be done. Again, be cognizant of how much you are opening your maple. Try to open it slowly, over two or three years, being careful not to expose too much trunk to unfamiliar direct sunlight. I have crawled under dissected maples where I could not even see my hand in front of my face. After fifteen minutes of pruning and I was enjoying my favorite book and lemonade in the translucence of my new tree room. Again, try not to nit pick except to break out small deadwood that has accumulated throughout the branch tips. Make larger cuts that conflict with each other, looking at the tree as a whole as you select your cuts. If you make a hole that looks too big on one side of the tree, make another on the other side of the tree. My consulting arborist friend, Ed Milhous always said that a polka dot dress must have dots covering the entire dress rather than one great big dot in the middle. Your tree should be the same. Fill the tree with uniform continuity, polka dots everywhere, and you will see the analogy. The branch design possessed by the weeping dissected maples is generally exquisite. Your pruning will open the tree and expose this structure. It can be obvious with large windows to the interior or done subliminally where you only see a hint of the branches due to your impressionist talents. Again if one branch can do the job of two, remove the weakest rather than nit picking both. Hold the back of your hands in front of your eyes, together. Now open them so you see eight fingers and imagine them as branches. You could cut ever other one in half to thin your tree or you could remove one of your hands to get the same affect with one cut. Remove more wood with fewer cuts. The look you get will be cleaner and less crowded. A graphic designer once told me “white space” is good in your marketing material. I believe air space in your maple can be artful as well. You will be pleasantly surprised!
  • We cannot have a discussion about pruning such magnificent trees without a refresher course brought to us by our late friend and scientist, Dr. Alex Shigo. If you know me, you’ve heard it all before; C.O.D.I.T., how trees deal with wounds and survive. Each cut we make is a wound on our trees. Where we make these cuts is a matter of longevity and survival for our trees. I consider it more important where we place our cuts on the branch than I do how much of the branch we remove. In other words, we must make each cut at that place called THE BRANCH COLLAR, just outside the branch collar. The branch collar belongs to the tree, not the branch and must be left on the tree after the branch is removed. Thou shall not leave a stub or flush cut anywhere on our Japanese maples. I consider this to be critical and paramount during our pruning performance. If we respect this collar our pruning can actually make a tree healthier. To read more about branch collars, I direct you to your State Extension agents web site or simply Goggle Alex Shigo Tree Pruning, then sit back and enjoy. Any of the sites will lead you to pictures and prose about this marvelous phenomenon.
  • Let’s sum everything up like this:

  • Try not to remove a limb that is greater than half the diameter of the tree’s trunk. In fact, I would probably stop with a quarter to a third with older trees.
  • Prune out limbs that cross, rub, conflict or interfere with a better, healthier limb.
  • Always remove deadwood and take the time to remove even the smallest pieces. I believe the less deadwood in a tree’s crown the longer the tree will live.
  • Structure prune young trees after they have been in the ground for 2-3 years. You can, of course prune out deadwood at any time of the year, anytime in a tree’s life.
  • Try not to nit pick a tree by making hundreds of tiny cuts. Instead, try to find whole limbs that are interfering and remove the whole limb, when possible.
  • Try never to reduce your tree in height. Woody plants are genetically programmed to grow every year. When we do not allow them to follow this programming we create monsters and trees that become delinquent. The right Japanese maple in the right place is the best rule, as is the rule for any species in any location. These elegant maples come in every size, color and shape. Fill the space correctly and logically and then apply your artful talents to paint your own personal picture!

Artful, botanically correct pruning is always positive. Listen to what the plant is asking for. Know the species you are pruning and then work with the individual to bring out everything it has to offer. Pruning is art and art comes from inside each of us, and—as Dr. Shigo said so many times—there is no way to show it unless we touch our trees!

Happy Pruning, Peter!

P.S. If you are not sure what to do or become confused, just call your favorite arborist. I will guarantee they will come running to help you with your masterpiece. If not, call me!

Copyright 2008 by Peter Deahl. All rights reserved.

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