Japanese Maple Bonsai do really well in sunny and airy locations, but when temperatures rise to 30 °C or above, it should be placed somewhere with indirect sunlight to prevent damaging the leaves. The Japanese Maple is frost-hardy, even when trained as a Bonsai.
A Japanese Maple Bonsai must be watered daily during the growing season. During the hotter days in the growing season, it's sometimes necessary to water your tree several times, if the soil is well-drained and the tree is healthy and vigorous. Avoid watering with calcareous water as the Japanese Maple prefers a neutral or slightly acid pH-value.
Solid, organic fertilizers contain all the required micronutrients, and they take effect slowly and gently. They are very well-proven, especially for more mature Japanese Maple Bonsai. Be sure to follow the instructions carefully for the proper dosage. If you'd like a stronger growth on young plants or raw material, you can combine your regular dosage with a liquid fertilizer once a week. Avoid fertilizers with a high nitrogen concentration to avoid unnecessarily large leaves and internodes.
Trimming shoots and twigs can be done year-round. Strong branches should be pruned in autumn or summer, when callus growth is quick, to prevent excessive bleeding. When pruning thick branches we advise using a cut paste product to prevent fungal diseases that can enter through pruning wounds. The Maple is particularly vulnerable to some fungal infections and diseases. New growth should be pruned back to one or two pairs of leaves. Mature Bonsai with a delicate ramification can be pinched in order to keep the twigs thin. After the first leaf pair has unfolded, remove the soft little tip of the shoot between them to prevent the twigs from thickening. This method weakens the tree in the long run and should be applied specifically and thoughtfully.
The Japanese Maple Bonsai should be repotted every two years. It has strong roots that grow quickly and usually fill the pot in a short time, so be sure to prune the roots efficiently as per the instructions in the repotting Bonsai section. Use a well-drained soil mixture.
The Japanese maple can easily be propagated by planting seeds, cuttings, or air layering in the summer.
Pests and diseases
The Japanese Maple is a very sturdy tree species, but it can be affected by sap-sucking insects known as aphids in spring. Get rid of aphids with a standard insecticide spray, and follow the direction on the label. Verticillium wilt is a fungal disease that can cause the Japanese Maple Bonsai to partially or completely die. This disease is not treatable and can be transmitted to other trees via your Bonsai tools. You can identify it on fresh cuts as black spots in the wood. If you suspect Verticillium is present in your tree(s) be sure to thoroughly clean and disinfect your tools.