Cryptomeria is a national symbol of Japan and part of Japanese culture, representing longevity, resilience, beauty, and harmony.
Exotic evergreen coniferous plant, native to the mountain forests of Japan and China. It is very popular for growing as a room bonsai. Cryptomeria has a positive effect on the microclimate of the room by releasing phytoncides in the air, which have a disinfection effect and protection from harmful microbes. It is believed that this tree protects from evil spirits.
Placement
Cryptomeria prefers light places without direct sunlight. In hot weather, it is better to move the plant to the shade. During the winter months, additional lighting from artificial light sources is required.
Temperature regime
Bonsai cryptomeria prefers a warm room temperature. Its optimum temperature is approximately +18…+24 °C during the day and at least +10…+15 °C at night.
Avoid sharp temperature changes and cold winds, which can negatively affect the plant. During the dormant period (from October to the end of March), the recommended temperature for indoor bonsai is +10…+13 °C.
Lighting
Cryptomeria needs bright, diffused light. It is important not to expose it to direct sunlight, as this can cause burns. In the room, the best place is near an east or west side window.
Soil
Prefers moist, nutrient-rich soils, acidic or slightly alkaline. A mixture of Akadama, pumice and Lava (see here) is suitable, which provides drainage and air exchange. As organic additives — leafy soil and humus.
Watering
Regular moderate watering is required to maintain normal soil moisture. Avoid hardening and crusting when the soil dries out. Spraying of the crown is recommended, especially in winter in centrally heated rooms when the air becomes dry. Humidifiers can be used to increase air humidity.
If there is a lack of moisture, the needles of the tree turn yellow and fall off. For watering and for spraying use soft and necessarily warm water.
Fertilizers
The tree is fertilized once a month in spring using a special bonsai fertilizer. At other times, cryptomeria does not need additional nutrition. You can use liquid or granular fertilizers. In the second case, a special basket (see here) will be needed, through which watering will take place and fertilizer will be distributed.
Transplanting
Transplanting the tree is done in early spring. Young trees (up to 3–4 years old) can be transplanted every year, older trees up to 9 years old — once every 3 years. When transplanting, the roots are pruned and the soil is renewed. You can fertilize the plant after transplanting only after 1 month.
Shaping and pruning
Branch pruning is being done in the spring, removing shoots at the base of all branches and near the trunk. This will enable the crown to be thinned for better air circulation.
Winterization
During winter, Cryptomeria is best kept in a cool room (about +10 °C) with medium watering and protection from the dry air of heaters.
Diseases and pests
Yellowing and falling needles can indicate too dry air, overwatering or lack of light. It is important to provide the plant with optimal conditions.
Cryptomeria can suffer from spider mites if the air is too dry. In this case, treat with green soap and increase humidity.
