Pruning Bonsai

Bonsai need regular pruning both above and below ground throughout their lives. How often to prune depends on how fast the particular kind of tree or bush grows, the size of the pot and the growing conditions.The first place to prune is below ground. Roots eventually fill the soil in a small bonsai pot, so they need to be pruned back to make room for fresh soil. Root-prune deciduous bonsai in early spring or late autumn, and evergreen bonsai in early spring or late summer.The way to root prune is to lift the plant out of its pot and slice back the root ball all around and underneath with a sharp knife. After teasing roots on the outside of the ball outwards, put the plant back in the pot and pack new soil among the roots. Using a stick _ a chopstick is appropriate _ to pack down the soil makes sure that no air spaces are left which would dry out the roots.Now turn your attention to the top portions of your bonsai. The time to prune the stems is now, while the plant is dormant, and then again while it is actively growing.Bonsai respond to stem pruning just as other plants do. Pinch off the tips of any shoots whose growth you want to slow. Shorten a stem where you want the remaining part to branch. Rub off buds or cut stems back to their origins where growth is congested. To make a pine, spruce or juniper bonsai bushier, pinch back the new growth just as its expanding.Because bonsai are viewed at such close range,
you'll want to make pruning cuts especially neat. Avoid damaging the remaining leaves when you shorten expanding growth on spruce, for example, by reaching within a tuft of foliage with a pair of tweezers to tweak off all but a few new leaves. Fiskars and ARS make small, fine-pointed pruning shears that are ideal for working with bonsai.

Pruning Bonsai

Some bonsai benefit from having all their leaves pruned off just after they fully expand. Timed correctly, this leaf-pruning forces a second flush of leaves that are smaller and, hence, better proportioned to the plant.As an added benefit, that second flush of leaves often offers more dramatic autumn color than the first flush would have.On some trees, such as maples and elms, you can leaf-prune twice each season, as the first and second flush of leaves fully expand. If there is any chance of injuring buds at the bases of the leaf stalks, just cut off most of each leaf with a scissors or small pruning shear. The stalk will come off, perhaps needing some help from you, as new leaves appear.Leaf pruning is not for every bonsai. Don't do it on evergreens or on fruiting bonsai that are bearing fruit. And leaf-pruning is stressful, so avoid it on any tree that is weak or sick.The rigorous root and shoot pruning needed for bonsai is itself weakening, so take extra care to give bonsai perfect growing conditions in every other respect. This means water and fertilizer as needed, as well as good light. Many bonsai are dwarfed, cold-hardy trees and, as such, like to be kept as cool as possible this time of year.