The care of azalea bonsai is easy. Important for bonsai care is: Keep the bonsai evenly moist, use azalea fertilizer and an acidic bonsai soil like Kanuma when repotting. If you pay attention to this, azaleas can be called as bonsai for beginners.
Satsuki azaleas (Rhododendron indicum) belong to the group of hardy outdoor bonsai trees and should therefore be kept outdoors. These trees are mainly cultivated as bonsai trees because of the immense abundance of flowers.
We only fertilize these bonsai in our nursery with or after flowering (around mid-May) until September nitrogen-rich with mineral fertilizer. It is important when fertilizing azaleas that the bonsai fertilizer is adjusted to the very acidic pH value of the soil.
It is best to use a fertilizer for azaleas. Organic fertilizers such as Biogold or Hanagokoro are also well suited to azaleas. These fertilizers can be given before flowering because it takes a couple of weeks to really take effect.
The common liquid bonsai fertilizers are also suitable. Before flowering, it is best to give the amount indicated on the bottle. After flowering (where more leaf growth is desired) you can also give double.
During the flowering period, the azaleas should not be poured over the flowers, otherwise they will wither quite quickly. At the same time, azaleas need a lot of water. The best thing to do during the flowering period is to submerge the azalea bonsai until no more air bubbles rise. Sometimes several times a day. If possible, use lime-free water. Water that is too hard can lead to long-term damage to the tree (stunted leaves, yellowing). Rainwater is best suited for watering.
In Japan, Yamagoki moss is often found on the soil surface. It will be put on to keep the surface a little bit more humid. This has a positive effect on the many fine surface roots.
In summer full sun to half shade. It is best to have full sun if you have time to water a bonsai several times a day, especially during the flowering period.
The Satsuki azaleas tolerate temperatures down to -15°C in unheated foil tents according to our own experience. Wintered in bark mulch up to the first branch Satsuki azaleas survive such temperatures without complaint. A leaf loss of up to 50% can be considered normal here.
Every three to four years (or when the roots fill the pot) after flowering repot the azalea bonsai with root cut. Since the end of the flowering season can fall in July and it is already very hot and dry in our region, you can also repot in spring, but you must ensure a frost-free location afterwards. To hide the ugly yellow color of Kanuma soil you should simply apply a layer of Akadama mixed with humus 1:1 as a top layer.
For Azalea bonsai you should use a lime-free bonsai soil. The Japanese Kanuma bonsai soil is well suited for azalea bonsai. Peat-containing earth mixtures from the garden market should be avoided, despite their low pH values. Once slightly dried, these substrates are difficult to wet again. We do not add other bonsai substrates such as expanded slate. Kanuma has everything a good azalea soil needs.
Pests are not common on azalea bonsai. After an import, spider mites and other sucking insects are occasionally found. However, these can be combated well with the commercial agents against spider mites.
Azaleas can easily be propagated from cuttings. Propagation via seeds is not common.
Despite the shrub-like structure, a very good tree structure can be achieved by cutting and wiring. In japanese bonsai nurseries, azalea bonsai with enormous trunks are to be admired.
When applying bonsai wire, care must be taken as the wood of the Satsuki azaleas is relatively brittle and breaks quickly when bent excessively. Thus one should distribute necessary strong bends over several years.
If you want to wire an azalea bonsai you have to work very carefully. Azaleas have a very thin bark that can be easily injured. It is advisable to use the softer aluminum wire for azaleas. Due to its larger diameter, it presses less into the bark than copper wire.
In principle, all styling techniques (pruning, wiring) should only be started after flowering. After flowering, the remains of the flowers are plucked with the fingers. Than you should start with pruning.
The Satsuki azaleas tolerated cutting very well and after being cut back into the old wood they sprout again at all possible and impossible places. Here, shoots that grow steeply upwards or downwards should be removed immediately with a sharp bonsai scissors.
For larger cuts (the wood is very hard so a concave pliers for bonsai is required), wound closure agent should then be applied to promote better healing of the wounds. Otherwise these wounds are usually visible for a long time on the smooth azalea bark.
The Satsuki azaleas look good in all styles except the broom style. They are usually designed freely upright (Moyogi style) or slightly inclined (Shakan style). From time to time you can also see bonsai styled with exposed stilt roots. Azaleas are much more common to see designed as a half-cascade or cascade.
Matching bonsai pots
Glazed bonsai pots are well suited for Satsuki azalea bonsai with its splendour of blossoms. Since they belong to the winter-hardy bonsai, a frost-proof, handmade bonsai pot should be selected if possible. In our experience, the inexpensive pots (made for indoor bonsai) are also almost 100% frost-resistant. However, we do not guarantee frost resistance for these pots.
2 colors on a tree
Unglazed bonsai pots are also suitable for older azalea bonsai with thick trunk. Dark brown or grey unglazed pots would fit quite well.
Azalea bonsai with its roundish crown fit quite well into an oval bonsai pot but also rectangular pots are suitable. For rectangular pots, we would choose a pot that has slightly rounded corners. Higher, round pots are particularly suitable for azalea bonsai in semi-cascade style. Drip trays are not needed because azalea bonsai should not be placed in the apartment.
Suitable pots for prebonsai in the growing phase are the plastic bonsai pots. The dark brown colour of the pots does not go so well with azaleas. However, these plastic pots are extremely frost-resistant and UV-stable. For 2-3 year old young plants, it is best to use plastic plant pots or clay pots as in Japan.
The broad funnel-shaped flowers stand alone or together in pairs. Their colour spectrum ranges from pure white to pink, orange to red. There are even two-coloured flowers or trees with different colours on a tree.
The bark of azalea bonsai is extremely thin. During wiring your Azalea bonsai you should work carefully so that it does not come to damage.
There are hundreds of breeding forms (e. g. Eikan, Nikko, Chinzan, Kaho, Osakasuki, Hakurei, Kinsai) that would make an exquisite bonsai collection on their own.
The Japanese term Satsuki is derived from the 5th month in the Asian lunar calendar and refers to the main flowering time. It starts at the end of April and lasts until June. During this time a Satsuki Azalea Bonsai is covered over and over with flowers, so that no leaves or branches are to be seen any more. The flowering period is usually 6 weeks if the flowers are protected from wetness from above (rain, watering can).
The leaves are about 2.5 to 3cm long, oval with a tip and bristly on both sides. Satsuki azaleas are semi evergreen, an acid soil loving shrubs. Depending on the hibernation temperature, the leaves remain on the tree.