Learn About Bonsai Tree Styles!

Basic Styles

Bonsai can be classified into five basic styles: formal upright, informal upright, slanting, cascade, and semi-cascade. These classifications are based on the overall shape of the tree and how much the trunk slants away from an imaginary vertical axis.

The numerous Japanese bonsai styles are principally variations of these five basic styles. The styles given in this bulletin apply to trees with single trunks. The single trunk style is the basic design that is simplest to shape because the one trunk determines the overall composition.

Formal Upright

The formal upright style has classic proportions and is the basis of all bonsai. It is the easiest for a beginner to develop because it requires the least experimentation, avoids the problem of selective pruning, and should almost immediately become a displayable bonsai.

In this style, the form is conical or sometimes rounded and the tree has an erect leader and horizontal branches. One of the branches is lower and extends a little farther from the trunk than the others (Figure 1). Also, the lowest two branches are trained to come forward on the front side of the tree, one slightly higher than the other. The third branch of this style extends out in the back of the tree at a level between the two side branches to give the plant depth (Figure 2).

Sequoia sempervirens in the formal upright style

 Figure 1. Note the off-center placement of this redwood (Sequoia sempervirens) in its oval container. This tree was trained in the formal upright style, which is considered the easiest for the novice bonsai grower.

Mugho pine in the formal upright style

 Figure 2. The formal upright style features a straight trunk, and a bottom branch that is lower and extends further from the trunk than its opposite. This specimen is a Mugho pine (Pinus mugo 'Mugo').

Plants in the formal upright style look best in oval or rectangular containers. Do not center the plant when placing it in the container. Plant it about a third of the distance from one end.

In choosing a nursery plant for this style, make sure the trunk rises from the ground in a fairly straight line. The trunk should be straight and not fork or branch out for the total height of the tree. Trim off the small branches or twigs that are too close to the base and near the main stem. These branches detract from the overall composition. 

Informal Upright

The informal upright style has much the same branch arrangement as the formal upright style, but the top -- instead of being erect as in the formal upright style -- bends slightly to the front. This bend makes the tree's branches appear to be in motion and enhances the look of informality (Figures 3 and 4).

The informal upright style looks best in an oval or rectangular container. It should be planted, not in the center of the container, but a third of the distance form one end.

Trident maple in the informal upright style

 Figure 3. This trident maple (Acer buergerianum) bonsai, is trained in the informal upright style. The style is similar in branch placement to the formal upright style, but differs because of the angularity of the trunk.

San Jose juniper in the informal upright style

Figure 4. The trunk in the informal upright style bends slightly to the front. This specimen is 32 years old, a San Jose juniper (Juniperus san jose) in training since it was a seedling.

Many nursery trees are naturally slanted. This makes them well suited to the informal upright style. Check the tree's slant by looking down at the trunk from above -- from this angle the top should slant to the front. If this view is not attractive, you may move the root ball to slant the tree in another direction.

If you choose a vertical tree at the nursery, and want to train it in the informal upright style, simply tilt the plant when potting it. When you do this, trim the branches and foliage so they are scaled to the size of the tree. 


In the slanting style, the trunk has a more acute angle than in the previous styles. The lowest branch should spread in the direction opposite to that in which the tree slants. The top of the tree is bent slightly toward the front (Figures 5 and 6). The lower branches are arranged in groups of three, starting about one-third the way up the trunk.

Common juniper in the slanting style

 Figure 5. This common juniper (Juniperus communis) , estimated to be about 80 years old, was collected in 1979, and has been trained in the slanting style of bonsai. In this style, the lowest branch spreads in the opposite direction to the slant of the tree.

Lantana in the slanting style

 Figure 6. In the slanting style the trunk has a more acute angle than in the informal upright style. This specimen is a Lantana, salvaged from a construction sight in 1959.

Slanting trees in nature are called "leaners" -- trees that have been forced by the wind and gravity into nonvertical growth. The attitude of the slanting style falls between the upright and cascade styles. This style looks best planted in the center of a round or square container. 


In the cascade style the trunk starts by growing upward from the soil, then turns downward abruptly, and reaches a point below the bottom edge of the container. For this reason, the container should be placed on the edge of the table, or on a small stand (Figures 7 and 8).

Elephant bush in the cascade style

 Figure 7. Elephant bush (Portulacaria afra), trained in the cascade style, has a characteristic leader, which descends below the bottom edge of the container. A cascaded bonsai usually looks best in a round or hexagonal container.

Akebia in the cascade style

 Figure 8. The cascade style of bonsai represents a natural tree growing down the face of an embankment. This specimen is a three leaf Akebia (Akebia trifoliate) estimated to be about 30 years old.

The cascade style has most of its foliage below the soil surface. This style is representative of a natural tree that is growing down the face of an embankment.

Training a tree in the cascade style takes longer than in the slanting style. Choose a low-growing species instead of forcing a tree that normally grows upright into an unnatural form. Bend the whole tree forward so one back branch is vertical and the side branches fall naturally.

A cascaded planting usually looks best in a round or hexagonal container that is higher than it is wide. The tree should be planted off-center from the cascading side. 


The semi-cascade style has a trunk that is allowed to grow straight for a certain distance, and then is cascaded down at a less abrupt angle than in the cascade style (Figures 9 and 10). The cascading branches are thought of as the front of the tree, and the back branches are trained closer to the trunk than in the other styles. The semi-cascade should not reach below the bottom of the container, but should go below the level of the soil surface.

Shimpaku juniper in the semi-cascade style

 Figure 9. This Shimpaku juniper (Juniperus chinensis 'Sargentii' 'Shimpaku') in a hexagonal container was trained in the semi-cascade style. Prostrate junipers and flowering plants are well adapted to both cascade and semi-cascade styles.

Cotoneaster microphylla in the semi-cascade style

Figure 10. The semi-cascade style has a curving trunk that does not reach the bottom of the container as it does in the cascade style. This example is a little leaf Cotoneaster (Cotoneaster microphylla).

Plants that are well adapted to the cascade and semi-cascade styles are prostrate junipers, and flowering plants such as chrysanthemums, wisteria, willows, and star jasmine.

Before potting a tree for bonsai in any of the five styles, keep in mind the image of how the tree will stand in the container. Don't plant a tree one way, and then uproot it to make a change. Keep your overall theme in mind when planting bonsai. Upright trees should have a stabilized look in the container; slanted and cascaded styles often have their upper root surfaces exposed to imitate plants that grow this way in nature.

No matter what style you choose -- whether single trunk specimens or groups of trees from single roots -- everything depends on your selection of plant material, and your ability to visualize the bonsai's final form.


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