/ Plant Profiles

Azalea

Azalea Characteristics

Azalea are very popular in landscapes, although they do tend to be a favorite food among deer. The Japanese have a fondness of Azalea in their gardens, often hybridizing them and carefully manicuring the plants’ growth to very exacting standards. They also make an excellent plant for bonsai due to their small leaves, attractive flowers, smooth bark, and ease of care.

Natural Habitat

Azaleas of Japan

Azalea are a broad-leaf evergreen found in deciduous forests of the north-east. They enjoy the early spring sun before the leaves of their canopy counterparts open. Once the canopy above is in full-leaf the azalea are shrouded in shade where they receive relief from the summer sun. The constant supply of oak leaves gives the Azalea an acidic mulch, keeping a rich loam that maintains even moisture.

Growth Habit

Trunks

Azalea Trunks In Development

Azalea are naturally a multi-trunked shrub to around 5 feet. Their Rhododendron cousins tend to grow much taller. Developing a single trunk of significant size takes a lot of time and a bit of luck.

Azalea Back-budding And Sucker Growth

The plants do back-bud readily on old wood and have a propensity to sucker from the base. The best way to develop a trunk is to keep pruning back the suckers to avoid multi-trunking and to allow as much top-growth on the single trunk as possible.

Bark

Mature Azalea Bark

The bark of young wood is brown and flaky strips. As the plant matures, the bark becomes smooth, similar to that of a European Beech.

Scars On Azalea Trunks

They do not heal-over particularly well and will leave attractive dimples where branches have been cut, giving the impression of age and adding character.

Deadwood

Deadwood On Azalea Bonsai Trunk

Azalea deadwood can be very attractive, particularly on trunks. While not as traditional as on Junipers, the effect can work quite well in bonsai.

Dead Branches On Azalea

Dead branches do not tend to look as attractive as trunks, giving the appearance of neglect rather than age.

Flowers

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The real draw of Azaleas are the flowers, and it is no different in bonsai cultivation. The flowers of Azaleas come in variations of every color of the rainbow except green and blue. Some have flowers with multiple colours in the same flower, or different solid-colored flowers on the same plant. Flowers can be single of double blossoms. The shapes and sizes also vary. The one thing that all azaleas seem to have in common is when they do flower, they get completely covered.

Leaves

New Growth On Azalea

The leaves of azaleas are evergreen, about 1/4 inch oblong.

Azalea Leaves Rounder Azalea Leaves

The leaf variations between species are slight, generally some being a bit rounder than others or a bit shinier. The leaves are a good size for bonsai purposes and will not increase or decrease in size with variations in care. The leaves may exhibit a red hue in autumn depending on the species, but the real show are the spring flowers.

Caring For Azalea Bonsai

Light

Azalea are an under-growth, broad-leaf evergreen. As such, they are adapted to more shade than some other trees will tolerate. An azalea will tell you it’s happy in its location based on the rich, shiny green color of its leaves.

Healthy Green Leaves And Weaker Underfed Leaves

Too much sun (or too little fertilizer) and the leaves will start to fade into a yellow-green color.

Watering

Azalea naturally grow in a rich, loamy soil of the forest floors. They are used to the acidic conditions created by oak leaves, and the consistent moisture ensured through a supply of leaf-litter. In bonsai culture, keep the soil evenly moist; avoid extremes of dry or wet.

Pruning

Azalea Pads Of Leaves On Bonsai

Azaleas have a habit of thin, leggy shoots and a propensity to sucker at the base. Pruning of the foliage can be done at any time. Long shoots can be cut back to develop pads on branches. Shoots which are long and out of place should be cut so they conform to surrounding growth on the same branch (or pad). After flowering, seed heads should be removed to promote stronger new growth.

Feeding

Fertilizing is good for promoting good plant health and color. Use a general purpose (20-20-20) at ½ the manufacturers rate and feed every 2 or 3 weeks apart while the tree is actively growing. During the winter feeding is not necessary for the tree should be going dormant. Resume feeding when buds first appear in the spring. An acidic fertilizer may be beneficial but is not required.

Over-Winter Care

Azaleas are hardy to temperature zone 5. However your tree is in a container which now needs to be sheltered from extreme cold over the winter. Trees should be left outside to grow, this is where they do best. As the weather begins to change, leave trees outside till approximately Thanksgiving. At this time consider placing bonsai inside a garage or shed to over winter. The trees will be dormant and will not need light. Water the tree well and keep in a location in which it will not be forgotten. It’s important not to let it dry out over the winter period. The tree should be moved back outside when the harsh weather breaks. Generally around March/April.

Propagation

Azaleas will readily produce roots on any branch that receives the consistent moisture of soil. Grafting is not done as there are no root stocks hardier than another. Plants can be easily air layered and cuttings can be taken, often just by sticking a branch in the ground in Spring or Fall without rooting hormone! Unless trying to create a new strain, Azaleas are rarely propagated by seed.