Source: Wikipedia - Bonsai is the art of growing trees, or woody plants shaped as trees, in containers. Bonsai is sometimes confused with dwarfing, but dwarfing more accurately refers to researching and creating cultivars of plant material that are permanent, genetic miniatures of existing species. Bonsai does not require genetically dwarfed trees, but rather depends on growing small trees from regular stock and seeds. Bonsai uses cultivation techniques like pruning, root reduction, potting, defoliation, and grafting to produce small trees that mimic the shape and style of mature, full-sized trees.
The purposes of bonsai are primarily contemplation (for the viewer) and the pleasant exercise of effort and ingenuity (for the grower). By contrast with other plant-related practices, bonsai is not intended for production of food, for medicine, or for creating yard-sized or park-sized landscapes. As a result, the scope of bonsai practice is narrow and focused on long-term cultivation and shaping of one or more small trees in a single container.
'Bonsai' is a Japanese pronunciation of the earlier Chinese term penzai. A 'bon' is a tray-like pot typically used in bonsai culture. The word bonsai is sometimes used as an umbrella term for all miniature trees in containers or pots, but this article focuses primarily on bonsai as defined in the Japanese tradition. Similar practices in other cultures include the Chinese tradition of penjing and the miniature living landscapes of Vietnamese.
Container-grown plants, including trees and many other plant types, have a history stretching back at least to the early times of Egyptian culture. Pictorial records from around 4000 BC show trees growing in containers cut into rock. Pharaoh Ramesses III donated gardens consisting of potted olives, date palms, and other plants to hundreds of temples. Pre-Common-Era India used container-grown trees for medicine and food.
The word penzai first appeared in writing in China during the Jin Dynasty, in the period 265AD – 420AD. Over time, the practice developed into new forms in various parts of China, Japan, Korea, Vietnam and Thailand. Notably, container-grown trees were popularized in Japan during Heian period, a period of cultural growth when the Japanese experienced and adopted their own versions of many Chinese practices. At this time, the term for dwarf potted trees was "the bowl's tree" (hachi-no-ki), denoting the use of a deep pot. The c.1300 rhymed prose essay, Rhymeprose on a Miniature Landscape Garden, by the Japanese Zen monk Kokan Shiren, outlines aesthetic principles for bonsai, bonseki, and garden architecture itself.
At first, the Japanese used miniaturized trees grown in containers to decorate their homes and gardens. During the Tokugawa period, landscape gardening attained new importance. Cultivation of plants such as azalea and maples became a pastime of the wealthy. Growing dwarf plants in containers was also popular. Around 1800, the Japanese changed the term they used for this art to their pronunciation of the Chinese penzai with its connotation of a shallower container in which the Japanese could now style small trees.
One of the oldest-known living bonsai trees, considered one of the National Treasures of Japan, is in the Tokyo Imperial Palace collection. A five-needle pine (Pinus pentaphylla var. negishi) known as Sandai-Shogun-No Matsu is documented as having been cared for by Tokugawa Iemitsu. The tree is considered to be at least 500 years old and was first trained as a bonsai by 1610. Older plants have been made more recently into bonsai as well.
Sources of bonsai material
All bonsai start with a specimen of source material, a plant that the grower wishes to train into bonsai form. Bonsai practice is an unusual form of plant cultivation in that growth from seeds is rarely used to obtain source material. To display the characteristic aged appearance of a bonsai within a reasonable time, the source plant is often partially-grown or mature stock. A specimen may be selected specifically for bonsai aesthetic characteristics it already possesses, such as great natural age for a specimen collected in the wild, or a tapered, scar-free trunk from a nursery specimen. Alternatively, it may be selected for non-aesthetic reasons, such as known hardiness for the grower's local climate or low cost (in the case of collected materials).
The practice of bonsai development incorporates a number of techniques either unique to bonsai or, if used in other forms of cultivation, applied in unusual ways that are particularly suitable to the bonsai domain.
With limited space in a bonsai pot, regular attention is needed to ensure the tree is correctly watered. Sun, heat and wind exposure can dry bonsai trees to the point of drought in a short period of time. While some species can handle periods of relative dryness, others require near-constant moisture. Watering too frequently, or allowing the soil to remain soggy, promotes fungal infections and root rot. Free draining soil is used to prevent waterlogging. Deciduous trees are more at risk of dehydration and will wilt as the soil dries out. Evergreen trees, which tend to cope with dry conditions better, do not display signs of the problem until after damage has occurred.
Bonsai are repotted and root-pruned at intervals dictated by the vigour and age of each tree. In the case of deciduous trees, this is done as the tree is leaving its dormant period, generally around springtime. Bonsai are often repotted 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.
Specimens meant to be developed into bonsai are often placed in "growing boxes", which have a much larger volume of soil per plant than a bonsai pot does. These large boxes allow the roots to grow freely, increasing the vigor of the tree and helping the trunk and branches grow thicker. After using a grow box, the tree may be replanted in a more compact "training box" that helps to create a smaller, denser root mass which can be more easily moved into a final presentation pot
Special tools are available for the maintenance of bonsai. The most common tool is the concave cutter (5th from left in picture), a tool designed to prune flush, without leaving a stub. Other tools include branch bending jacks, wire pliers and shears of different proportions for performing detail and rough shaping.
Soil and fertilization
Bonsai soil is usually a loose, fast-draining mix of components, often a base mixture of coarse sand or gravel, fired clay pellets, or expanded shale combined with an organic component such as peat or bark. The inorganic components provide mechanical support for bonsai roots, and—in the case of fired clay materials—also serve to retain moisture. The organic components retain moisture and may release small amounts of nutrients as they decay.
In Japan, bonsai soil mixes based on volcanic clays are common. The volcanic clay has been fired at some point in time to create porous, water-retaining pellets. Varieties such as akadama, or "red ball" soil, and kanuma, a type of yellow pumice used for azaleas and other calcifuges, are used by many bonsai growers. Similar fired clay soil components are extracted or manufactured in other countries around the world, and other soil components like diatomaceous earth can fill a similar purpose in bonsai cultivation.
Opinions about fertilizers and fertilization techniques vary widely among practitioners. Some promote the use of organic fertilizers to augment an essentially inorganic soil mix, while others will use chemical fertilizers freely. Many follow the general rule of little and often, where a dilute fertilizer solution or a small amount of dry fertilizer are applied relatively frequently during the tree's growing season. The flushing effect of regular watering moves unmetabolized fertilizer out of the soil, preventing the potentially toxic build-up of fertilizer ingredients.
A bonsai display presents one or more bonsai specimens in a way that allows a viewer to see all the important features of the bonsai from the most advantageous position. That position emphasizes the bonsai's defined "front", which is designed into all bonsai. It places the bonsai at a height that allows the viewer to imagine the bonsai as a full-sized tree seen from a distance, siting the bonsai neither so low that the viewer appears to be hovering in the sky above it, nor so high that the viewer appears to be looking up at the tree from beneath the ground. Peter Adams recommends that bonsai be shown as if "in an art gallery: at the right height; in isolation; against a plain background, devoid of all redundancies such as labels and vulgar little accessories."
For outdoor displays, there are few aesthetic rules. Many outdoor displays are semi-permanent, with the bonsai trees in place for weeks or months at a time. To avoid damaging the trees, therefore, an outdoor display must not impede the amount of sunlight needed for the trees on display, must support watering, and may also have to block excessive wind or precipitation. As a result of these practical constraints, outdoor displays are often rustic in style, with simple wood or stone components. A common design is the bench, sometimes with sections at different heights to suit different sizes of bonsai, along which bonsai are placed in a line. Where space allows, outdoor bonsai specimens are spaced far enough apart that the viewer can concentrate on one at a time. When the trees are too close to each other, aesthetic discord between adjacent trees of different sizes or styles can confuse the viewer, a problem addressed by exhibition displays.
Indoors, a formal bonsai display is arranged to represent a landscape, and traditionally consists of the featured bonsai tree in an appropriate pot atop a wooden stand, along with a shitakusa (companion plant) representing the foreground, and a hanging scroll representing the background. These three elements are chosen to complement each other and evoke a particular season, and are composed asymmetrically to mimic nature. When displayed inside a traditional Japanese home, a formal bonsai display will often be placed within the home's tokonoma or formal display alcove. An indoor display is usually very temporary, lasting a day or two, as most bonsai are intolerant of indoor conditions and lose vigor rapidly within the house.
Exhibition displays allow a large number of bonsai to be displayed in a temporary exhibition format, typically indoors, as would be seen in a bonsai design competition. To allow many trees to be located close together, exhibition displays often use a sequence of small alcoves, each containing one pot and its bonsai contents. The walls or dividers between the alcoves make it easier to view only one bonsai at a time. The back of the alcove is a neutral color and pattern to avoid distracting the viewer's eye. The bonsai pot is almost always placed on a formal stand, of a size and design selected to complement the bonsai and its pot.