How to Prune a Boxwood Bonsai

Prune boxwood bonsai after the first flush of growth. Allow it to grow unrestricted in the spring, as this makes the tree stronger. After May, prune and pinch it to refine the leaves. Pinching and pruning makes the tree bushier and more dense because you force new growth in certain sections.

Use sharp pruning shears to prune boxwood bonsai. Pinching requires the use of your forefinger and thumb to remove the growing tip on new shoots. By doing so, the plant has to grow buds farther back on the branches.

Identify new shoots in the late spring and summer; they are fragile and soft to the touch. Pinch them between your thumb and forefinger and pull them off.

Eliminate some of the foliage on the top of the boxwood bonsai to let more light penetrate through the plant. Thinning encourages "back budding" and prevents the inner branches from becoming bare.

Remove diseased, damaged or weak branches. Cut them off at the joint they share with wood you want to keep.

Remove the oldest branches to open up the canopy. This is called thinning. It allows sunlight to reach lower branches, resulting in the growth of new branches. Leaves fall off if the branches are shaded. Target the older branches because they are less productive than younger ones. They are recognizable because they're more brittle than new shoots and branches.

Prune boxwood bonsai severely only if absolutely necessary. It takes them a long time to recover. In some cases, they won't grow well again for years. If you need to severely cut them, though, do it in the late winter to early spring.