A Detailed Guide to Controlled Cultivation Techniques for Tree Bonsai: Master the Key Points to Grow Bonsai Well

  Tree bonsai generally refers to those that use woody plants as the main material, processed through techniques such as wiring, pruning, grafting, and carving along with horticultural cultivation, to present the scenery of trees in nature within a pot. Many people treat bonsai as their own child. Raising a child requires nurturing and education to go hand in hand, not only providing water, fertilizer, light, and ventilation so it survives, but also controlling and guiding it according to different growth conditions so it grows and takes shape in the direction we intend. This is artistic creation. It takes ten years to grow a tree and a hundred years to cultivate a person. If bonsai relies only on wiring and pruning a few times at a certain stage, carrying out crash-course creation, it is difficult to achieve satisfactory results.

  Controlled cultivation aimed at the appreciation goal: to make tree bonsai into a work of taste, care must be differentiated according to different appreciation goals. For example, for flower-viewing and fruit-viewing stump bonsai, necessary control measures should be taken in cultivation. When the proportion of root, trunk, and branch thickness has not reached the requirement, they should not be allowed to bloom and bear fruit, so as to avoid consuming large amounts of nutrients. Therefore, flower buds should be removed promptly, the earlier the better, and at the same time, fertilizer water with relatively high phosphorus content should be avoided as much as possible, so as to transform them from reproductive growth to vegetative growth. Only in this way can energy be concentrated, strengthening the trunk and branches, developing in the designed direction, and promoting early formation. Only after formation should flowers and fruit be cultivated, so that it can become a flower-viewing and fruit-viewing bonsai work of taste and class.

  Tree bonsai is a living, constantly changing work of art, which requires the creator to continuously prune, adjust, and control it without interruption; otherwise it will return to a wild natural state and have no artistic value at all. Therefore, the creator should do the following small but important tasks well.

  [Spring Bud Removal]

  When most trees sprout in spring, buds tend to emerge at the base of the trunk. For species such as Chinese elm, Japanese bush cherry, pomegranate, firethorn, and Chinese loropetalum, new buds sprout regardless of whether on old trunks or new branches, and most are vigorous buds. If these buds that are not in the right positions are not removed in time, they will not only consume nutrients, but once they become branches they will also cause the disadvantages of an overly dense crown and poor ventilation in the inner canopy, directly affecting the normal growth of the retained branches, and making the tree prone to pests and diseases. Therefore, it is best to remove them promptly before leaf expansion. Some buds will repeatedly emerge and need to be removed many times continuously until the retained branches and leaves have grown long. If this work is done well, it will greatly reduce the workload of later branch thinning. However, note that before removing buds, first carefully observe the entire tree's layers, line veins, and outer contour to see whether there are improper gaps that need filling. If there are, then when removing buds here, a few buds should be kept in appropriate positions to prepare for filling the gaps. Although it is a small matter, supplementing branches this way is much more natural and much more beautiful than borrowing branches from the wrong position, and the work will be more perfect after it takes shape in the future.

  [Summer Branch Thinning]

  Branch thinning at this time is to clear away sneaky shoots and thief branches that were not fully removed during bud removal. For most trees with strong sprouting ability, although buds have been removed, many useless branches will sprout on the inner side of the trunk, and they grow quickly and are very strong. After summer begins and before the plum rain, fine thinning pruning should be carried out pot by pot. Cut off inner-canopy branches, clustered branches, overlapping branches, and overly dense branches, with emphasis on some water sprouts outside the reserved range. Most of these branches grow inside the crown and are not easily found from the outer crown. By the time they extend outside the crown, they have already grown quite thick. Moreover, some useless branches grow around the branching points of old branches and are relatively dominant, absorbing large amounts of nutrients and very easily causing disadvantaged old branches to gradually degrade and decline. Although this is a natural renewal phenomenon in plant growth, in bonsai creation it must be prevented in time to ensure that useful branches have sufficient nutrients, good ventilation, and ample light. During the free-growth stage, the crown has many dense branches, and it is difficult to find the attachment points of branches from the outer contour alone. Therefore, before seeing clearly, do not cut easily. Be sure to search layer by layer and section by section within the branch groups, accurately distinguish useful branches from water sprouts, and avoid blindness and carelessness. Thinning branches is not only beneficial for ventilation and light penetration in the tree's inner canopy, reducing pests, diseases, and unnecessary water and fertilizer consumption, but also helps the cultivator see clearly whether the direction of branch and trunk line veins and the density layout are appropriate, so as to discover problems in time and correct and control them in time.

  [Controlling Strong Branches]

  So-called strong branches refer to individual branches among the branch pads that need to be retained which have already reached the required thickness proportion (usually the trunk-to-branch ratio should be 3:1, extending section by section). A truly meaningful bonsai art work must have roots, trunk, and branches that are overall well-proportioned and coordinated, so that it can embody the charm of shrinking a dragon into an inch and the ruggedness of an old tree, and have natural beauty. Trees exhibit apical dominance during growth; this is very normal. Now I have found another problem: during the free-growth process, people neglect observation, causing individual middle and lower branch pads to be over-cultivated and exceed their proper scale, with proportions thrown off balance, resulting in trunk and branches being similar in thickness and branch pads becoming bloated, which is very ugly. To avoid similar occurrences, the cultivator should observe frequently, especially during the vigorous growth period, and must not miss the good opportunity for pruning. The solution is also very simple: when a branch pad's thickness has reached the required proportion, cut the main branch and side branches of the branch pad shorter, and it can be pruned in one go to the length required by the styling, but there is a premise: a small number of leaves must be retained on the remaining branch forks, and not a single leaf may be left off, otherwise this branch will die from lack of photosynthesis, especially in the high-temperature midsummer when extra care is needed. If the branch forks that need to be retained have no leaves, the method of sectional gradual cutback can be adopted: first retain a slightly longer section of branch with leaves, and after buds sprout and leaves grow behind, cut back again, continuing to cut until the required length is reached. In this way, one can avoid the detour of reworking due to uncoordinated branch pads and delaying formation.

  [Light Control to Support the Weak]

  Plants all have the characteristic of phototropism, and the side facing the sun grows stronger than the side facing away from it. Although a tree bonsai has only one best viewing side, to achieve the effect of being viewable from all four sides, the growth vigor on all four sides must be balanced so that its width and thickness reach a relatively full and coordinated scale. This requires turning the orientation of the potted tree at appropriate times during cultivation, letting the weaker-growing sides and branch pads enjoy more sunlight, enhancing photosynthesis, and increasing growth speed; and letting the vigorously growing side face the shaded side to slow its growth speed. This support and suppression makes the entire tree scene grow evenly on all four sides.

  The above cultivation practices may seem tedious and trivial, but they are actually also creation. They run through the entire cultivation process of bonsai, and if handled well they will yield twice the result with half the effort. The reasoning is simple, but not many people can truly do it and do it well. As the saying goes, true skill shows in the small details. To be realistic, in this regard we really do need to learn well from Japanese bonsai practitioners; their rigorous, serious, and meticulous professional spirit toward bonsai is undoubtedly something we lack. This must be acknowledged.