Pruning an Acer should really be kept to a minimum as the most graceful shape can come from a tree that has been left to develop naturally.
But if you wish to prune your Acer to take a certain shape or hard prune an overgrown tree then this is best carried out when it fully dormant from late November to January.
This is because Acer’s bleed sap when they are pruned at other time’s of the year, thus weakening the tree.
When pruning your Acer make sure to prune back to a bud (this means cutting just above the bud). If you leave any excess wood above the bud, the dieback can become diseased.
Acer’s like most trees need pruning to take out any damaged, dead or diseased wood, and branches that have crossed over or that are growing in the wrong direction.
Smaller Acer’s do not like hard pruning, it is much better to prune them more regularly and gently. They also tend to get congested toward the centre of the tree, so it advisable to open it up to allow light and air movement through the tree. To do this, cut back a few of the older branches right back to the main trunk.