People contact us all the time asking when to prune Japanese maple trees. We believe that there is no wrong time to prune Japanese maple trees (or any other tree, shrub or flower). Certain times are better than others, but it can be done as needed at any time.
Prune it when it needs to be pruned. When you wait you might miss the opportune time and then problems with growth and shape compound themselves.
We’ve never had an issue arise due to our liberal pruning methods.
Japanese maples tend to go through growth spurts in the spring and fall seasons. You can expect your tree to put out 3-6 inches of new growth per year. Spring growth is more vigorous than fall growth.
Energy is focused on putting out new growth, which leaves less focus on callusing over new cuts. Sap running in the spring can make newly pruned Japanese maples slightly more susceptible to fungal infections.
We prune in the spring and fall and have never had an issue.
That being said, the best time to prune Japanese maple trees is during the winter and summer months.
Winter is a good time to shape the frame of your tree. Pruning in the winter months helps stimulate new spring growth. With the leaves off the tree, its easy to see which branches are rubbing or growing at odd angles and need to be removed.
Summer pruning stimulates less new growth. Its easy to find dead branches that need pruning and its easy to shape the tree based on how the leaves are laying.
Age trumps date.
The age at which we prune our Japanese maple is more important to us than what time of year we prune it. We don’t prune our young Japanese red maple seedlings until they are about 2 years old. We snip the tops off to encourage multiple branching. Otherwise, we’d end up with a tall, thin whip-like tree.
When a cut is made on a branch, the tip will die back to the next bud break. From that bud break, 2-4 new branches will begin to grow. The direction that the bud is pointing determines which direction the new growth will branch out from. For each cut made, 2-4 new branches will begin sprouting. This adds fullness to the shape of the tree.
Japanese maples are like children.
When you begin shaping them early, they are likely to grow nicely and keep the proper shape. If you come across one that hasn’t had the proper guidance, its not too late to help shape them into beautiful happy trees.
Not all cuts are made to encourage growth. Cutting back to a main branch or the trunk will eliminate new growth. Its important to make your cut just before the branch collar. Don’t leave stubs and don’t over compensate and make your cut flush with the tree. The branch collar belongs to the main branch and cutting it will cause unnecessary injury.
Most ornamental Japanese maples are grafted. You will want to pay attention to where the graft union is on your tree as some can be higher up on the trunk. Be sure to prune off any branches that are below the graft union or you’ll have two trees in one. Plain versions of Japanese red maples are usually used as root stock and the leaves will look oddly different from the ornamental variety growing on top.
When we prune Japanese maple trees, we don’t just look at shape. We remove branches to promote air flow and allow sunshine to reach all the leaves. We remove any branches that are dead or diseased, rubbing other branches, and any growing inward or in odd directions.
On the before and after pictures above you can see how unnecessary branches were removed from the inside of the tree allowing better air flow. We also removed a large branch from the left side that threw the shape off balance.
Much like humans, the older a Japanese maple tree gets, the harder it is to bounce back from injury. As they age, it takes more effort to heal from cuts, protect themselves from the elements or adjust to stress. There are a couple guidelines to follow when pruning Japanese maples trees. These guidelines are especially important when dealing with older trees.
- Don’t remove a limb that is more than half as large as the trunk.
- Don’t remove more than 1/3 of the crown.
Another tip: Bypass pruners or lopping shears make the best, cleanest cuts. Look for blades that come across each other in scissor action. Avoid tools that make guillotine- like cuts. The blades smash and splinter the wood.
Have any questions or comments about when to prune Japanese maples? Post ’em below!