Although technically a tree, dwarf Japanese red maples remain shrublike, topping out at 4 feet in height, with semi-dwarf cultivars averaging 7 to 9 feet. The small trees benefit from regular pruning to maintain an attractive shape and to keep the plant's branches off the ground. Prune annually in late winter or early spring after frost danger passes for your area. Prune on an overcast day to avoid stressing out the small tree with heat or excess sunlight.
Check the branches of your dwarf Japanese maple for dead, diseased and damaged wood. Diseased or damaged wood may be wounded, scarred, discolored or sport growths like galls. Dead wood won't move in the wind and will feel hollow.
Clip off dead, diseased and damaged wood at its base. In between cuts, spray your pruning tools with disinfectant spray to avoid contaminating healthy parts of the tree.
Prune low-growing branches that touch the ground back by several inches, cutting back to a lateral branch or just before a leaf.
Remove branches that crisscross other branches, since their rubbing will cause damage. Also remove shoots that grow vertically.
Remove limbs from crowded areas to promote new growth and to open up the tree canopy to light and air circulation. Eliminate up to 1/3 of the growth at a time.