Basic Bonsai Methods
The two main methods of creating a bonsai could be described as the "subtraction" and the "addition" methods. Subtraction shapes the tree by pruning away unnecessary branches and twigs. In the addition method, you start the plant from seed or a cutting, and gradually encourage it to develop into the shape you want for your finished design.
These two methods are analogous to those used in sculpture: indeed, bonsai is often described as "living sculpture". In the subtraction method of real sculpture, the carver cuts away the wood or stone to reveal the basic design, and subsequently refines the surface detail. The addition type of sculpture involves the craftsman building up a pliable material like clay and shaping it until the final intake is complete.
However, because a bonsai tree is formed from living material that grows and changes, the addition and subtraction methods are not mutually exclusive: most bonsai are made from a combination of the two methods. A tree may be grown from seed for some years, then severely pruned to reduce and shape the branches. The new growth that sprouts from the cut-back branches is pruned in its turn.
Another technique is to prune a young tree from a garden center drastically, then allow it to grow freely for another year or two before you shape and refine it by less severe pruning. You can repeat these processes over a period of time, as often as is necessary.
Wiring is another process that enables the grower to refine an already pruned tree and alter its basic shape by training the branches and trunk into a different growth pattern from their natural one. Wiring will not damage the tree and, with practice, you can easily leant the skill.
Pruning a Bonsai to Shape
You can create a bonsai within minutes by buying a vigorous, well-shaped young shrub, such as this pyracantha, from a garden center or nursery and pruning its branches into a more refined shape. This is the basic "subtraction" method of creating a bonsai.
The first illustration shows the chosen pyracantha as it arrived from the garden center, with a mass of narrow branches radiating out at all angles, and thickly covered with shiny green leaves.
The second illustration shows the effect of pruning and repotting. The pruning has revealed a slanting trunk line. Thinning and shortening the branches has produced a pleasing triangular-shaped bonsai. The apex is slightly domed, and the lower branches spread out in a balanced asymmetry. After the roots were pruned, the whole bonsai was planted into a speckled cream, oval pot.
Wiring a Bonsai
If the branches and trunk of a tree are fairly flexible, you can wire them into a different direction, or give the tree a different shape. ^ Wiring can also improve a bonsai created by pruning a ready-made shrub, or one grown from seed, or a design created by a combination of the two methods.
The general principle of wiring is as follows. Wind the wire in a spiral, at a 45-degree angle, along a branch or up a trunk. Bind it tight enough to encourage the branch or trunk to maintain the new angle or curve into which you will twist or bend it when adjusting the tree's shape. Leave the wire in place for up to a year, but be sure to remove it before it bites into the surface of the bark, or it will create an ugly, long-lasting scar that may take years to fade away.
Propagating a Bonsai
By propagating a plant, you can encourage bonsai characteristics which a garden-center plant may lack. Grow a seedling, or a cutting, in a pot until it is big and strong enough to be planted out in the ground. This will thicken the stem and branches, producing growth in two years that could take twenty in a pot.
Trim the branches to encourage bushy growth. For a fibrous root system close to the trunk, prune the roots in winter by severing them with a sharp spade, or by digging up the plant, pruning, and then replacing it.
When the plant is ready, lift it and prune the roots and branches into the basic bonsai shape. Plant it in a pot to grow on, and continue to prune and train each year.
Pruning for Shape
For beginners, one method of creating a bonsai is especially recommended. This is to visit a nursery or garden center, and buy a healthy small shrub or tree. Study it from all angles before pruning it to a more distinctive style and shape.
The advantages of this method are several. Firstly, you obtain an instant result instead of waiting for years to create a bonsai from seeds or cuttings: the example of a rockspray cotoneaster shown below was pruned in only 15 minutes. Secondly, you can obtain material much more easily than find a suitable tree in the wild. It is also a relatively cheap method. Finally, if you are not happy with your first attempt, your second may turn out to be a veritable masterpiece.
Of course, to have success with this method of pruning, it is vital to buy a suitable plant.
Pyracanthas and cotoneasters are ideal for this method, as well as the smaller shrubby varieties of Lonicerajasminum nudiflorum, and Chaenomeles japonica. The species should be one that is hardy and adaptable, with small leaves that will suit the scale of a bonsai. If you want seasonal features, the flowers and fruit of the original plant should be small and neat. A deciduous species is best for a first attempt, because its basic structure is clearly visible when the branches are bare, and you can prune it to shape in late winter, or in early spring just before the leaves unfold.
Select a shrub with a thick, sturdy trunk, that has a good line, to form a basis for your bonsai. The shrub should have many branches in sufficient numbers to complement the weight of the trunk, and the foliage or twigs should be compact, and growing up to the trunk.