Techniques
Shaping and dwarfing are accomplished through a few basic but precise techniques. The small size of the tree and the dwarfing of foliage are maintained through a consistent regimen of pruning of both the leaves and the roots. Various methods must be employed, as each species of tree exhibits different budding behavior. Additionally, some pruning must be done seasonally, as most trees require a dormancy period and do not grow roots or leaves at that time; improper pruning can weaken or kill the tree.[2]
Most species suitable for bonsai can be shaped by wiring. Copper or aluminum wire is wrapped around branches and trunks, holding the branch in place until it eventually lignifies and maintains the desired shape (at which point the wire should be removed). Some species do not lignify strongly, or are already too stiff/brittle to be shaped and are not conducive to wiring, in which case shaping must be accomplished primarily through pruning.[2]
To simulate age and maturity in a bonsai, deadwood features called "jin" and "shari" can be used to good effect with coniferous bonsai, especially: "jin" are created by removing the bark from an entire branch to create a snag of deadwood, while "shari" involves stripping bark from areas of the trunk, simulating natural scarring by limbs being torn free. Care must be taken when employing these techniques, because these areas are prone to infection, and removal of too much bark will result in losing all growth above that area. Also bark must never be removed in a complete ring around the trunk as it contains the phloem and will cut off all nutrient flow above that ring.
Bonsai care
Watering
Because of limited space in the confines of a bonsai pot, bonsai care can be quite difficult. The shallow containers limit the expanse of the root system and make proper watering practically an art in itself. Watering techniques vary, with some growers preferring to water with a fine rose on a watering can or hose, while others immerse their trees in a water-filled basin to the height of the container lip. While some species can handle periods of relative dryness, others require near-constant moisture. Watering too frequently, or allowing the soil to remain soggy can promote fungal infections and "root rot". Sun, heat and wind exposure can quickly dry a bonsai tree to the point of drought, so the soil moisture should be monitored daily and water given copiously when needed. The soil should not be allowed to become "bone dry" even for brief periods. The foliage of some plants cultivated for bonsai, including the common Juniper, do not display signs of drying and damage until long after the damage is done, and may even appear green and healthy despite having an entirely dead root system.
Repotting
Bonsai are generally repotted and root-pruned around springtime just before they break dormancy. Bonsai are generally repotted every two years while in development, and less often as they become more mature. This prevents them from becoming pot-bound and encourages the growth of new feeder roots, allowing the tree to absorb moisture more efficiently.
Wiring
Bonsai wiring is one of the most powerful tools to control the shape of the tree. The best time to wire a tree is in spring or fall when there is not as much foliage and the tree will not be too stiff. (Trees become stiff in winter while dormant because the sap pressure of the trunk and branches is much lower.)
To wire the tree, wrap the trunk. Then wrap each branch in spirals of bonsai wire so that the branch may be bent. The tree will then train the branch to grow in the desired direction. Another method of wiring involves attaching weights to the branches, causing them to sag and creating the impression of age.
Generally, wire is left on for one growing season. The tree should not be allowed to outgrow the wire, since this could cause the bark to become bound to the wire, making removal traumatic. When the time comes to remove the wire, it should be cut away in small pieces (rather than winding it off) as this will cause less damage to the foliage.
The thickness of the wire used should be in proportion to the size of the branch— larger branches will require lower gauge wire. Two pieces of thinner wire paired together can be used in lieu of heavier wire. It is bad form to let any wires cross; this is most readily accomplished by starting from the base of trunk and working up.
When bending the branches, one should listen and feel for any sign of splitting. When bending a branch near the trunk extra caution should be used, as the branch is generally most brittle near the trunk. It is possible to gradually bend a branch little by little over the course of several months.
When working with the branches, consideration should be given to the style desired.
Posts
No comments:
Post a Comment