Pruning a Japanese Maple

(Question)

Can you please assist in how to best prune a mature Japanese Maple? It is healthy, about 5 feet tall and about the same width. The tree is about 7 years old and doing well.

It needs to be trimmed back a bit. I assume now is the time while it is still dormant?

How do I trim, please?

Thank you,
Ingrid Hann

 

(Answer)

Japanese maple is a beautiful specimen tree and a wonderful focal point for any garden.  It sounds like you have a healthy, vibrant tree.   Young trees are prone to thin, whip-like branch growth that many owners feel detract from the overall appearance of the tree.  However, these wispy branches can grow into strong scaffold branches, and their early pruning encourages more growth of these spindly branches.  Patience with a young tree will be rewarded as these thin branches fatten and build out the structure of the tree.

Japanese maples are not very fussy in terms of when they can be pruned.  Pruning in winter will allow you to clearly see the structure of the branches you are trying to shape and pruning in summer gives you a good perspective on how the foliage fills out the overall shape of the tree, and as well as on the health of individual branches.  As with any tree or shrub, you will want to prune out any dead branches and twigs.  Pruning in summer is also less likely to encourage new branch growth, but avoid pruning more than 20% of the crown, and no more than a quarter of the foliage on any parent branch.  Removing too much foliage at one time inhibits the tree’s ability produce nutrients and can expose the inner branches and trunk to sun damage.

This article contains detailed information on good pruning practices for different types of Japanese maples, and how to sustain and enhance structure as the tree grows.   You may be also interested in the Toronto Master Garden’s guide to growing Japanese maples found here.