Azalea - An Informal Upright Bonsai:An azalea can be used in bonsai however - it hurts to cut off all those gorgeous flowers! In this case we can suggest an informal upright style. This style is softer and less rigid than the formal upright style, allowing a little more scope for styling and choice of tree. It is more appropriate for flowering plants than a formal style.
The trunk of an informal upright curves or bends, changing direction but still maintaining a vertical silhouette, with the tip directly above the base of the tree. The curves in the trunk should go to the left or right, not towards or away from the viewer. Your tree should create the image that stress such as wind, competition for light or lack of space has forced an old tree to mould itself into a position necessary for its health and survival.
No branches should grow from the inside of curves. The lowest and strongest branch should grow from the outside of a curve about one third the way up the tree. The tree is planted in one of the outer thirds of a rectangular or oval pot and this branch extends across the remaining two thirds of the pot. The next branch up from there should extend to the back, followed by one to the other side. This pattern is repeated, with each successive layer becoming shorter and slightly closer together. Branches should have a graceful downward curve as well, as this contributes to the appearance of age. There is more flexibility in an informal upright style - many beautiful trees do not conform exactly to this pattern, yet would be classified as informal upright bonsai because of their overall appearance.
Flowering bonsai such as azaleas, cherries, bougainvilleas and crab apples are often planted in glazed pots that reflect or contrast with flower color. Shape is usually oval rather than rectangular, and in a more delicate style than that used for a more formal bonsai. Care must be taken that the pot does not attract more attention than the tree.
The root system of an azalea consists of a mass of very fine hair roots, which often completely fills the pot. It is impossible to comb and separate the roots as you would other plants. If you have removed a large amount of the foliage, you can remove a proportionate amount of the roots. The bottom half of the root mass can simply be cut off! The resulting shallow root system can be trimmed to fit the pot it will grow in with a little room for new soil to encourage new root growth. A mild solution of a "plant start" fertilizer will encourage new root development, but no other fertilizer should be added until new foliage growth is apparent. New leaves will start to grow almost immediately. It is not unusual for an azalea to flower within a few weeks of this traumatic experience - apparently on the theory that this kind of stress might cause death, and flowers will ensure survival. While the tree itself has become smaller in bonsai, and often the leaves, flowers are still the usual size and often appear too big for the plant. An azalea, particularly, must never be allowed to become dry; other plants have different moisture needs. Any plant just root pruned needs careful watching for a few weeks, until it is growing well. Do not place in hot, direct sun until it is well established, even if it normally prefers it.
Shrubs and trees flower most often because of day length. Some flower when the day is long enough, some at the shortest day of the year. Temperature is also a possible factor - some need a cold, dormant period before they set buds, while others need warmth to be healthy. A good bonsai book will help, as will information on flowering houseplants, trees and shrubs. If in doubt, try to visualize where that plant would normally be growing. A tropical plant cannot need cold temperatures to stimulate flowering, but a crab-apple that blooms in spring after a cold winter very likely does.
Informal upright is a style, which allows a great deal of creativity, and is suitable for a large variety of plants, not all flowering. Many evergreens fit well into this style, as do maples. It is one most often tried by beginners, and often returned to regularly as skills and confidence develop. Experiment and enjoy!