Reed PughHow to prune a weeping maple

I hear some people say that they don’t like weeping Japanese maples (Acer palmatum ‘Dissectum’ and other cultivars) and my heart breaks. I feel that this can be one of the most beautiful trees with just a little work to enhance its form, but often they are left to their own devices and their beauty can be hidden by layers of branches.

Acer palmatum 'Crimson Queen' prior to pruning.  It is attractive, but needs some pruning to let more light in and accentuate the many branching layers. ©2013 BDG

Acer palmatum ‘Crimson Queen’ prior to pruning. It is attractive, but needs some pruning to let more light in and accentuate the many branching layers. ©2013 BDG

Naturally these plants tend to form a thick flowing coat of branches and leaves, somewhat reminiscent of Cousin It from the Addams Family. In time they will have many layers with the innermost dying from lack of light. While they can still be attractive without pruning, I feel that the thick outer layer obscures from view the beautiful branching inside. The form and branching is what makes this plant so desirable throughout the year.

Cousin It

Cousin It from The Addams Family

With some regular pruning you can have a stunning structural plant that is open to allow you to appreciate the foliage and branching, and it can easily be conformed to any size and be trained in any direction. Like most shrubs, they need to be pruned for aesthetic and functional purposes. I hate seeing contractors pruning azaleas, boxwood, holly and many other shrubs with gas pruners. While they might achieve the lollipop form they are seeking, it encourages a thick outer layer of leaves with no internal growth and a plant that must expand every year to survive.

Here is the maple after pruning. The leaves will have better color with the light and the many layers are highlighted. With new lighting underneath it will be beautiful at night and all year long. ©2013BDG

Here is the maple after pruning. The leaves will have better color with the light and the many layers are highlighted. With new lighting underneath it will be beautiful at night and all year long. ©2013BDG

Functionally, they need to be opened up to allow light inside so the inner branches won’t wither. Aesthetically, you want to accentuate the delicate branching and flowing form.

Last week, I helped a client prune a slightly overgrown and dense maple. The question I get most often is where do I start. For those who might be a little nervous, getting inside and pruning out the dead branches is a great place to start. Next, I look for branches that are going ‘against the grain’ or crossing the major flowing branches of the tree. The largest branches form a type of umbrella and they tend to flow out and down, and often branches form that go across this structure and they need to be pruned out.

Step back and see what has developed after this work. Always step back and look at your progress because it is best to come back and make another cut rather than regretting the loss of a branch you didn’t mean to cut.

This plant was so dense that the branching on the back had all died. With it open all the branching will strengthen and the natural layers have been highlighted.  ©2013BDG

This plant was so dense that the branching on the back had all died. With it open all the branching will strengthen and the natural layers have been highlighted. ©2013BDG

After the dead and crossing branches are gone it is time to start looking at the major structural branches. Always start at the top of the plant and make a couple of bigger cuts rather than making lots of smaller cuts.  The bigger cuts will produce the major structural changes you are looking for rather than small ones that will fill in quickly.  The idea at the top of the umbrella is to develop a strong and interesting form to support the rest of the plant.  It often means removing branches to accentuate a curve or decrease the congestion of multiple branching. Also, it can involve removing a branch that goes underneath and allowing a visual separation to create a layered effect.

The cuts you make will also dictate the future direction of growth. If you want your maple taller, then encourage branching on top that is pointing up, and lighten those branches by removing shoots pointing downwards. If you want a wider plant, then prune at a point where a branch is pointing outwards in the direction you want to expand.

This Maple lost its left side in heavy snow 5 years ago. Through selective pruning I encouraged branching to fill in the hole.  Also, I am encouraging a few upward branches to increase the height.  Opening the branching has also revealed an intricate and curving branching pattern.  ©2013BDG

This maple lost its left side in heavy snow 5 years ago. Through selective pruning I encouraged branching to fill in the hole. Also, I am encouraging a few upward branches to increase the height. Opening the branching has also revealed an intricate and curving branching pattern. ©2013BDG

It is pretty intuitive, you just need the courage to make the cuts necessary to enhance your beautiful weeping maple. Great words of guidance I learned years ago is to make few big cuts rather than lots of small cuts. I am not imposing my will on the plant, just opening it up to enhance its beauty. You can also come back later and make additional cuts. They are long-lived plants and pruning and care for them is a process.

Sometimes you might just make a few cuts and wait until next year to see how the tree responds. However you prune your maple, it is worth the effort to enhance one of the finest specimen trees available.

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Reed Pugh

About Reed Pugh

Horticulturist and landscape designer living in the suburbs of Boston, Massachusetts. Reed is passionate about gardens and plants and loves writing about horticulture, plants, garden accoutrements, best garden practices and whatever else comes to his frenetic mind. He tries not to take himself too seriously but has been known to 'geek out' on occasion. Reed, and his company Barking Dog Gardens, can be found at Reeds Garden Ramblings

3 thoughts on “How to prune a weeping maple

  1. Pam Pearse on said:

    Thank you for showing us how to improve the beauty of one of the most precious trees in my present garden. I need to ask how and when to move my little beauty from its birthplace to a holding pot and then what to do to ensure its health and longevity when removed then replanted to our new home far away.

    • Reed Pugh on said:

      Pam, there are a lot of variables.

      How big is the plant, how long has it been in its location, how long will it be in its pot.

      Let’s start with the basics, digging a maple would be best in the late winter before the tree has leafed out and the buds are still dormant. Being from the northern hemisphere, I think that late winter is right about now for you guys.

      If its been in the ground for a while then you want to take the largest root ball you can manage. In the US we have standards for root ball size based upon the caliper(diameter of trunk 4 inches above grade) of the tree. I would apply this generously to a weeping maple. A 1inch caliper tree should have a root ball 16inches in diameter and a 2inch caliper tree should have a root ball of 24″. Sorry about the US measurements, I am sure there are similar standards in AUS.

      Without much more info, it is hard to provide any more specific instruction.

      Since the tree is dormant, it does not need to be soaked in water as it will rot since the plant is not active. Just keep it lightly moist during travel.

  2. What a beauty. You are so right, Reed. Everyone – and everything – benefits from a flattering haircut to show off their best features.

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