Best time of year to prune acers - and it’s much later than you think

Pruning acers capitalises on their natural beauty and allows them to prosper and live longer in your garden. But you must know the correct time to do the work and the best method

The autumn brings different challenges for gardeners and the question of when to prune trees becomes an issue.

Gardeners are asking when is the best time to cut back acers and the answer is it's earlier than they think. The act of pruning Japanese maple trees capitalises on their natural beauty and allows them to prosper and live longer in your garden. But you must know the correct time to do the work and the best method. The Express reports gardening experts at Urban Forest Pro say the “best time” to trim most ornamental trees is in dormant winter months. They said: “For Japanese maples, it is recommended to do structural pruning in the winter and wait until late spring, after the leaves come out, for fine pruning.

“Summer can also be a good time for removing larger branches and for removing dead, damaged, or diseased wood.” Other professionals also say the colder months are the best time to prune. Bright Lane Gardens also say winter is the 'prime time' for pruning these trees. They said: “The best time to prune a Japanese maple tree is during the dormant season, which typically falls in winter to early spring.”

Pruning at this time has several benefits, including a clear view of the tree's structure because of the absence of leaves. This can allow you to make more accurate pruning decisions. In the dormant season, it is less stressful for the tree as its energy is stored in the roots and trunk, which helps avoid damage to its overall health.

Many pests and diseases which target Japanese maples are inactive in winter and reduces the chances of infestation or disease spread through cutting back your trees. If you prune before the growing season kicks off can spur the tree to “produce new growth” rather than “reduced growth” come spring, which is important for “shaping and rejuvenating the tree so it looks incredible”.

But it’s important not to over-prune as it could result in “reduced growth or stress” for the tree. When it comes to how to prune Japanese maples, always start with the dead, damaged, or diseased branches - they're “the first to go”. Removing these branches is beneficial for the tree's health and helps prevent further problems.

Thinning out the canopy by selectively cutting branches improves spacing, which enhances airflow and light penetration to the inner branches. This is crucial to “reduce the risk of diseases” such as powdery mildew and "promote better growth" When trimming your trees, make clean, precise cuts just beyond the branch collar - the swollen bit where a branch meets the trunk or another limb. Don't leave any stubs behind because they are an open invitation for disease and decay.

Experts also say gardeners should 'angle those cuts slightly' so water doesn't settle on the cut surface. Going too hard with the pruning shears can really “stress the tree” out, leading to “poor growth or dieback”. Instead of giving your trees major chop now and then, it's usually “more effective and less stressful” for the tree if you stick to light and regular trims.