Knowledgebase

trimming a Japanese maple #816852

Asked November 23, 2022, 12:47 PM EST

We are brand new owners of a Japanese maple in the backyard of a house we recently purchased. We've heard the best time to trim our tree is in the fall after the leaves have fallen off. Here we are, almost in December, but our leaves haven't fallen off. Well we can certainly wait. But it occurs to us that trimming now when the leaves are still on would be advantageous. We could see much better what we need to do. We want to change its shape a little Is this acceptable?

Clackamas County Oregon

Expert Response

Thank you for your question, Jim.  Although it may seem counterintuitive, the best time to prune deciduous plants is in late winter/early spring.  When you are pruning live tissue, you are "wounding" it, which makes it more vulnerable to insects, disease and, in colder weather, freezing of the unprotected cells.  In early spring, you should be able to see the shape of the tree better, and you'll get to know which are dead branches and twigs, and which are still viable enough to grow leaves.
Specifically as to Japanese maples, they do not need to be pruned at all, and it is not recommended that you do.  They do not need to have a central leader (trunk) removed to spread out; they do that naturally.  Of course, removal of diseased, dead or dangerous plant material can be done any time of the year.
Here is an OSU page on the traits and care of this species:  https://landscapeplants.oregonstate.edu/plants/acer-palmatum
I hope this is helpful.  Good luck!
Kristena LaMar Replied November 23, 2022, 1:50 PM EST

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