Satsuki Azalea Bonsai Care Guide
Rhododendron indicum is a flowering shrub native to Japan and has been hybridized there for over 500 years. In nature these plants can grow to six feet tall. The name "Satsuki" means fifth month and refers to the time of year this plant blooms. Azaleas and Rhododendrons used to be classified separately, however in the late 20th century the work of various botanists resulted in the two being merged under one genus. There are hundreds of azalea cultivars, Satsuki being a favorite of bonsai enthusiasts for its hardiness and small leaves.
The leaves of the Satsuki Azalea bonsai are small, glossy, and somewhat hairy. The flowers can vary from one to five inches in size and grow in pairs out of the terminal end of the shoot. This plant has an amazing color range, from white to purples to reds and pinks. There are also different patterns that can appear on the blooms – stripes, flakes, and margins of color on a different colored background.
The fascinating thing about this bonsai is that different color patterns can be produced by the same plant in different years. The trunk is grayish to brown, and may become very thick with lots of character. The following are a few tips to care for Satsuki Azalea bonsai.
Rhododendron indicum may be grown indoors or out. If kept outdoors, this bonsai should be moved to a frost-free location once the temperature drops below 48 degrees Fahrenheit, and in its dormancy should be mulched for root protection.
If kept in a garage or shed, check on the plant often during the dormant phase, as mice and rabbits find the soft bark to be a tasty treat. Satsuki needs about a half day of full sun – more than that can cause the flowers to wilt and fade.
Indoors, offer the plant a cool, sunny window. The rest of the time it can be placed in light shade or bright indoor light.
Satsuki Azaleas should be kept consistently moist, as they do not like any dry soil at all. Water once a day at minimum during the growing season.
Azaleas do not like lime so use rainwater if available, or lime-free tap water. This is particularly important in areas with hard tap water, because you do not want lime to build up in the soil. If there is no option but hard water, the pH can be adjusted in the soil by watering once a month with a mixture of one tablespoon white vinegar to one gallon of water.
These plants require very well-draining soil so that they don't sit in water.
Begin feeding in springtime, giving a weak formula of organic fertilizer made for acid-loving plants. Administer bi-weekly until the blooming period is done. After this time, feed once a month. You can use a lower nitrogen, higher phosphorus and potassium mix in late summer to autumn.
Popular Styles – semi-cascade, slanting, root-over-rock, windswept, twin trunk. The sturdy trunk on this plant lends itself to styles which are shaped to look like a tree.
In order to encourage new foliage production, all dead flowers at the plant's base should be removed as soon as the flowering season is over. During this time yearly growth should be trimmed; shoots grow in sets of five at the ends of branches and should be trimmed down to two. The rest of the shoots should be pruned to two sets of leaves. Prune secondary shoots in the middle of summer. The following explains how to shape an Azalea bonsai.
Azaleas can tolerate heavy pruning, in fact if cut down to a stump they will back bud profusely and may be shaped into virtually any bonsai form. Use a sharp bonsai tool to prune and use wound paste on the cuts.
This plant has very delicate bark and brittle branches, so if wiring is desired aluminum should be used. Raffia can protect the bark during wiring. This should be carried out in November. Allow the plant to dry out for about a week before doing any significant reshaping with wire.
Satsuki Azalea bonsai are highly sought after partly because of their ability to bud back vigorously on old wood. Propagate by softwood cuttings obtained in early summer.
This bonsai should be repotted in spring every other year, after flowering season is done. Azaleas have a fine, fibrous root system with sparse tap roots, and can tolerate quite aggressive root pruning. Cut the bottom of the root ball out at each repotting by cutting a cone shape that extends up to the base of the trunk. These thick roots should be removed to prevent root rot from poor drainage. Add some peat to the soil mix when transplanting, as these plants are acid lovers.
Insects/Pests & Diseases:
Satsuki bonsai can be vulnerable to aphids, caterpillars, scale, and whitefly. Scale and caterpillars must be removed by hand, other pests can usually be washed away with a stream of water or a gentle dish soap and water spray.
Leaf gall, petal blight, rust, and chlorosis can also affect azaleas. Make sure the plant has adequate ventilation and acidic enough soil. Do not spray the flowers with fungicide or insecticide as it will cause them to wilt.