A completely straight, upright and well tapered trunk with an even distribution of branches is necessary for this style. The first and main branch should be positioned at approximately one third of the trunk''s height. Subsequent branches should form a spiral pattern, becoming shorter and closer together nearer the apex of the tree, thus giving the bonsai a regular outline in the shape of a triangle.
Well developed surface roots help give the tree a convincing, stable look and rectangular pots are normally used for this style. This is one of the more difficult styles to create well and often appears somewhat contrived. Pines and conifers tend to be the most suitable material, because of their natural tendency to grow in this form.
The classic formal upright bonsai style should be reminiscent of a strong specimen tree, where branches have been able to grow naturally with no restriction and perfection of form has been attained.
Many bonsai can be classified in this category and this is the most popular style of tree both in bonsai and in nature, with the possibilities for design being endless. The trunk is not straight and may contain several curves, with branches usually emerging from the outside of these curves. This is a suitable style for all varieties of trees and shrub and is perhaps the least difficult style to create.
The apex will in most cases be directly above and in line with the base of the tree and for best effect be slightly angled forward to give the tree added depth. It is also a style where most shapes and colours of pot can be used, depending on the variety and size of the tree.
Informal upright is a popular style of bonsai tree, which is also very wide spread in nature, with many differing branch structures.
he slanting style is one of the easiest bonsai styles to achieve. There are no specifications as to how the branches and leaves should be shaped. The main criterion for this style is that the trunk of the bonsai should by slanting at an angle, either to the right or to the left (never towards the viewer or towards to back). Unlike the informal upright style, the tip of the plant should grow away from the axis of the base.
If you plan to achieve the slanting style with a particular plant, you should not plant the tree in the middle of the pot. If you plan to make the tree slant to the left, the base of the tree should be on the right side of the pot and vice versa. Rectangular and oval pots best suit this bonsai style.
Semi-cascade bonsai styles are very similar to cascade styles except for the fact that the tip of a semi-cascading bonsai does not grow below the base level of the pot. This is a relatively simple style to achieve as the branches are allowed to grow freely to resemble plants growing from cliffs. Flowering and fruiting plants are well suited for this design.
The Cascade style is easily recognized as the trunk dips below the bottom of the pot. This style represents a tree that is growing on a cliff top and has that cascade over and below the precipice of the cliff top. This style is suitable for most species, but is particularly prevalent amongst juniper, yew, pine and other confer bonsai
In nature this style of tree grows in areas densely populated by many other trees and competition is so fierce that the tree can only survive by growing taller then all others around it
The trunk grows crookedly upward and is completely without branching because the sun only hits the top of the tree. To make sure that it looks even tougher, some branches are “Jinned” (without bark). When the bark has been removed from one side of the trunk, the trunk is referred to as a “Shari”. The idea is to demonstrate that the tree really has to struggle to survive. These trees are often placed in small, round pots.
The broom style is suited for deciduous trees with extensive, fine branching. The trunk is straight and upright and does not continue to the top of the tree; it branches out in all directions about 1/3 of the way up the entire height of the tree. In this manner the branches and leaves form a ball-shaped crown which can also be very beautiful during the winter months.
Raft Style imitates those trees that have fallen down but continue to grow with the branches on one side becoming like individual trees. Commonly this style is found in a Straight-line or Ikadabuki imitating a tree trunk, occasionally you see a more Sinuous Root Connected Style (Netsunagari) which imitates a connected surface root that has meandering around and sent out new branches.