Within the realm of bonsai, the ancient art of training trees and shrubs to look like miniature mature trees, azaleas hold a prized position. Azaleas add color and bloom to the art of bonsai. When crafted with artistry and precision, an azalea bonsai flowers in clouds of pink, white and red.
While conventional azaleas and rhododendrons are typically shaped into hedges or compact shrubbery, azalea bonsai are most often shaped to resemble flowering trees. Even when not in bloom, their leaves provide visual interest.
Like all bonsai, it takes attention and care to create a realistic version of a mature tree. It’s important to attend to the trunk, branches, twigs, leaves and roots of the plant to ensure that they develop into the proper proportion and scale.
This is achieved not only by pruning the branches and roots but by improving the setting as well. The container, under plantings and soil aid in reaching the desired goal, which is the appearance of a natural tree in a natural setting, miniaturized.
| Scientific/Botanical Name | Rhododendron indicum |
| Description | An evergreen species, azaleas/rhododendrons are available in a wide range of cultivars. A number of forms exist, ranging from arching to upright habits. The shrubs grow best in soil that is acidic. |
| Position | Azaleas are grown outdoors in semi-shade. In the wild, azaleas are found in woodland areas, protected by tree canopies. Growing azaleas in a similar type of environment will promote optimal growth. The shrubs have shallow roots that can be easily damaged if grown in hot, sunny sites. In areas that experience frost, container-grown azaleas must be moved to protected locations during periods of extreme cold. |
| Watering | Azaleas need to be watered regularly during the growing phase. Plant wilting will occur if the container or the ground is allowed to dry out. Rain water is particularly beneficial to azaleas, because it contains the proper pH balance. |
| Feeding | Azaleas should be fed with an inorganic fertilizer every two weeks in the spring. When the shrub is in flower, it should then be fed monthly until the onset of winter. |
| Leaf and Branch Pruning | Prune the shrub at the end of the bloom cycle. Ideally, only a few of the newer shoots should be left at the site where new branches are desired. If the center of the shrub is bare, the shrub can be rejuvenated by a severe cutting-back. |
| Re-potting & Growing Medium | Younger plants grow more rapidly, and they should be re-potted every other year. Older plants should be re-potted every four years. Spring is the best time for re-potting azaleas, and flowers should be discouraged in the first year of re-potting because they place great stress on the sensitive azalea roots. Soil that contains equal parts humus, pumice and akadama is the ideal for azaleas. |
| Wiring | Typically, wiring is unnecessary for shaping azaleas. Selective pruning is usually sufficient to achieve the desired shape. Any wiring should be done on younger, more flexible branches only. |
| Notes | Azaleas and rhododendrons used to be classified separately, but azaleas are now classified under the rhododendron genus. |
Choosing An Azalea Bonsai
While a sense of proportion, artistry and patience are required to develop azaleas into stellar bonsai specimens, the plants are a good choice for beginners in the art of bonsai.
With proper care, their leaves can be developed to an ideal proportion. Azalea flowers, however, will bloom at their conventional size, but that is part of the charm of an azalea bonsai tree.
Many experts recommend that beginners start out with an established azalea bonsai. When purchasing a bonsai, it’s vital to buy a plant from a reputable source.
Even for experts, it can be challenging to determine if a bonsai has been cultivated properly. Whether purchasing an established specimen or starting from scratch, some varieties of azaleas perform better than others.
Azalea bonsai may be referred to by either their Japanese or botanical name. Three proven varieties of azalea for bonsai are:
- Kurume, Rhododendron obtusum
- Hiryu, Rhododendron obtusum
- Satsuki azalea, Rhododendron indicum
Satsuki azaleas are particularly popular with Japanese bonsai enthusiasts. The word “Satsuki” refers to their May to June blooming period. Satsuki is the fifth month of the Japanese lunar calendar. Other popular azaleas within the Satsuki cultivar group include chinzan, eikan, hakurei, kaho and osakasuki.
The Art Of Visualization
The key to successful bonsai art is to prune all but the branches, twigs, leaves and buds that are essential to the desired form and shape. To achieve this, it’s necessary to not only visualize the desired shape but to discern the parts of the plant that will most help the plant develop the desired design. In most cases, this takes a practiced eye. For the health of the plant, it’s important not to remove all new growth at one time.
Cultivating Azalea Bonsai
Soil Considerations
Azaleas prefer a well-drained acidic soil with a pH factor of between 4.5 and 6.0. Iron sulfate or ammonium sulfate can be added to make an alkaline soil more acidic. The soil should be rich in organic matter such as well-decayed leaf mold or compost. Azaleas thrive in soil that is kept evenly moist, neither too dry nor too wet. The roots of an azalea are very fine and will not tolerate over-wet soil, even for brief periods.
Tips To Promote Flowering
When it comes to pruning an azalea bonsai, it’s important to remember blooming periods. Azalea buds set in midsummer so any pruning that occurs after then will affect flowering the following spring. If experiencing sparse bloom, it’s sometimes advisable to sacrifice one year’s bloom to encourage a fuller bloom the following year.
Azalea bonsai will get most of the nutrients that it needs from a heavily organic soil. Too much fertilizer can limit flower formation. Azalea bonsai may be sparingly fertilized in the fall with a slow-release fertilizer formulated for acid-loving plants. Organic mulch, however, may provide all the nutrients that an azalea bonsai needs.
Cultivated carefully, azalea bonsai can be grown either indoors or outside, but are more likely to bloom best out of doors. Azaleas prefer a diffused light rather than full sunlight. They do well against a wall in an east- or north-facing location. Azaleas need protection in cold weather. Flower buds will be damaged by wind as well.
Root Pruning
It’s best to prune azalea bonsai roots in the spring. The soil is shaken gently to expose the roots. Up to one third of the roots can be pruned at any one time. The heaviest roots should be selected for pruning, with the fine roots left to supply nourishment to the plant.
It’s important to clean the container before replacing the plants so that root hairs do not become attached to debris stuck to the container. The azalea bonsai is then re-potted with fresh organic soil.
With the right cultivation, an azalea bonsai will improve with age, attaining a shape that is reminiscent of a cherry tree in full bloom.