Serissas make excellent bonsai with the right care and shaping. They are an evergreen shrub native to China, Japan, and Indochina (Southeast Asia) where it may be found growing in the woods and wet fields.
The serissa foetida has small oval leaves which are slightly larger than the serissa japonica’s. It may erupt with small white flowers several times per year giving it the nickname the “thousand star” serissa. Additionally, it naturally grows surface roots and an interesting bark pattern on the trunk which give them the desirable appearance of age.
Along with junipers this is one of the most common bonsai trees for beginners. Unfortunately this has also led to them getting a bad reputation for being easy to picky and easy to kill. With the right care this is not the case.
The most important thing learn about serissa bonsai is that they do not like change. They also do not like extremes. If a serissa bonsai is unhappy it lets you know by dropping its leaves and flowers.
Keeping your serissa watered properly is the most important part of its care. If you over or underwater your serissa it will lose its leaves. Serissas do not tolerate drying out and the shock may kill them. You should keep the soil moist but not wet or soggy. They also like a humid environment. We recommend that you place a humidity tray under its pot to create an area of humidity around the tree. Occasionally misting the leaves when the tree is not in bloom will also help. If you purchased the bonsai tree from a store that does not specialize in bonsai it may not be potted in the correct soil. Repotting your serissa in a well draining bonsai soil bonsai soil will help make it harder to overwater your serissa bonsai.
Serissa can be grown indoors or outdoors. (Outdoor in warmer climates) If kept outdoors a mix of full and partial sun in most zones will be fine. If kept indoors it can do well under fluorescent lighting, but keeping it in a room where it can get indirect light from an open window and supplementary fluorescent lighting tends to work best. If the serissa does not get enough light its growth may not be compact enough to give it a nice bonsai appearance.
Special care should be taken when bringing the plant indoors after it has been living outside or outside if it has been growing indoors. As noted earlier, serissa do not like change. If it had been growing in a sunny area try gradually moving it into a shadier location before bringing it indoors. Additionally, make sure the indoor location receives a good amount of light. If you use a grow light it may need to be left on for 12 hours per day. If the tree was indoors move it into a shadier outdoor area before moving it to a very sunny spot.
Serissa should be repotted during their growing season which is in spring. You should do this every 1-2 years when the tree is younger. Use a bonsai soil that holds moisture, but drains easily without remaining soggy. The leaves and roots tend to smell pretty bad when you prune them. This is normal.
Serissa tend to be pretty flexible on styles they can be trained into. They can be grown into informal upright, informal broom, oak style, and semi-cascade. They do not work very well as formal upright and formal broom. You can use the clip and grow method or wire on these trees. Wiring allows for more intricate designs. Serissa are often used in Chinese Penjing landscapes.