At some time your bonsai tree is going to require pruning to keep it in shape - and as this is a very crucial aspect of care of bonsai trees it is best to be very sure of what you're doing as, like Humpty Dumpty, once a branch has been cut you can't put it back together again.
Pruning not only encourages new growth, but is necessary to maintain the correct shape of your tree. Even with the youngest plant, you want to create an image of great age and endurance. Bonsai is also a very strict art form, with some very precise rules determining shape and style. If you know the basics for the care of bonsai trees you will know there are two main styles of tree - the very classic "Koten" formal style and the informal "Bunjin" style. However there are many subsets within these two categories. Some of the more common include upright, cascading, leaning, windswept, multi-trunk and roots over a rock. All require proper pruning to maintain the correct shape for the proper care of bonsai trees.
The natural shape of your tree will determine its basic style but your pruning will enhance or, if you get it wrong, destroy the beauty of your tree. You don't want to undermine all the other hard work you have done to deliver the correct care of bonsai trees. The first thing to research is the best time of year to prune your individual tree. This will depend very much on the variety of tree you have, but generally speaking the best time to prune new growth is in the spring, and old season growth is usually cut in the autumn.
One of the main ways to prune conifers, such as cedar and juniper, is to simply pinch back new growth that is appearing in the wrong place. To do this, hold the branch with one hand, pinch the growth you want to remove between the thumb and forefinger of your other hand, then give a sharp twist to snap off that growth. With deciduous trees, such as elm, it is better to use a very sharp pair of scissors, but make sure they are sterilized first as you don't want to introduce a disease to your tree. Trim shoots back to the next set of leaves; however make sure you leave that next foliage untouched so your tree is left with a natural look.
Some leaf pruning may be needed to remove unsightly dead or blemished leaves. Removing leaves is also vitalfor the proper care of bonsai trees such as fiscus to reduce leaf size. It also helps intensify the autumn leaf colour of deciduous bonsai such as maples. This type of pruning is usually done in mid-summer with a pair of scissors but, as previously stated, is suited to only some plants.
Pinching and leaf pruning take care of new growth but there will be times when you also need to cut away the previous season's growth. You need to look carefully at the shape of your tree before considering which branches to remove. You want to end up with a tree with an uncluttered, aesthetic shape. Branches which detract from the overall appearance will include any that cross each other, those that are growing from the underside of main branches or those that are growing back toward the trunk. While removing those you will also need to ensure you leave extra branches on any weak area of the trunk to help promote growth there.
Remember whatever you do to the top of your tree affects the roots below. You need to keep the branches and roots in balance. If you prune the top heavily and leave the roots alone you may trigger a growth spurt as nature tries to compensate.
Pruning the roots may be frightening for a beginner to contemplate, but it is in fact a fairly simple procedure and again essential for the proper care of bonsai trees. First gently remove your tree from its pot and comb out all the roots. Remove the larger, thicker roots leaving the smaller, finer roots as these are more efficient at absorbing water. Even when a severe prune is needed, never remove more than two-thirds of the root system.
