by George Buehler

Scientific Name: Rhododendron indicum
Common Name: Satsuki Azalea

The azalea is an evergreen shrub which can reach up to six feet in height. There are hundreds of azalea cultivars (probably thousands). The Satsuki azalea which originated in Japan is the most commonly used for bonsai. It produces flowers generally in May that are white, pink, red and sometimes flowers in multiple colors on the same plant.

The ideal growing environment for bonsai azaleas would be where the plant receives 4 to 5 hours of sun and the balance of the day receives bright filtered sunlight. The plant should be protected from the hot August sun to avoid leaf scorch.

The soil should never dry out but not be soggy. A fast draining soil is recommended. Most experts recommend using a soil mix containing Kanuma to keep the plant in slightly acidic soil. Many Japanese masters grow their azaleas in 100% Kanuma.

The Satsuki azalea is a prolific bloomer, normally starting in early May. Some experts allow their trees to bloom every other year to reduce plant stress. Others remove some to most of the buds, allowing only a few to open. Either way, dead blooms should be removed as soon as possible.

Fertilization should begin immediately after blooming and new growth begins, using an acid type fertilizer like MirAcid alternated with a balanced fertilizer. Fertilization should stop during August.

Many books recommend repotting after blooming has finished. However, here in the Ohio valley, this means that transplanting would occur from late May to early June which is entirely too late. Therefore, I transplant in early spring. When an azalea is transplanted, I do not allow the plant to bloom, removing the blooms as soon as they appear. The period between repotting depends on the age and condition of the tree. Young trees should be repotted every year, while older trees should be repotted every 4 to 5 years. Azaleas form dense mats of roots. When repotting, trim the root ball and cut out pie shaped wedges around the outside of the root ball so that the roots can grow into the gaps.

Pruning falls into two categories - heavy and maintenance. Heavy pruning should be done every other year as needed immediately after blooming is finished to ensure next year's buds are not removed. Maintenance pruning can be done throughout the growing season. Azaleas readily grow new shoots from old wood. New shoots at the ends of branches grow in groups of five. These shoots should be reduced to two, and the remaining shoots should be shortened to the first set of two leaves.

Wiring can be done thorough out the growing season, but the major wiring should be done after flowering. Older branches are generally brittle, so care should be exercised when making bends. The bark on azaleas can be damaged with careless wiring, and wire wrapped with raffia may be used to protect it. Prior to wiring, water can be withheld for a day or two which makes bending the stiff branches easier.

Here in the Ohio Valley, with the early spring rains, Daconyl should be applied every two to three weeks to prevent petal blight - starting as soon as leaf buds start to open. Another problem azaleas have is lace bugs. A tell tale sign of lace bug is a graying of the leaves, especially on the underside. This insect can be controlled with Malathion, Orthene or Isotox - following package directions carefully - if a spray schedule is started early in the season.

In the fall, azaleas should receive two or three hard frosts. Then they should be stored in an unheated garage or storage shed, or in a cold frame. Do not winter them outside.