Snow Rose Bonsai Care Guide
Also known as the Tree of a Thousand Stars because of the plethora of beautiful little white star-shaped blooms that appear on this shrub, Serissa foetida is an evergreen native of wet, open areas in China, Japan, and India. While the species name has its foundation in the putrid odor put off by the wood when nicked or trimmed, the smell is almost never noticeable except during pruning. Snow Rose is a cultivar of the only species in the Serissa genus, and is also sometimes referred to as Serissa japonica.
The foliage is made up of ovate, opposite growing leaves that are dark green in color and tiny in size, at just ½ inch or less in length. The gnarly, textured, flaking bark is very attractive to enthusiasts due to the aged look it gives to trees even when they're young. The plant may bloom any time during the year if given the ideal environment, with heaviest flowering still occurring in the growing season – spring to autumn.
This species should be kept as an outdoor plant in the warmer months. Once night temperatures stay below 50° F it may be brought inside or wintered in a cool greenhouse. It does not appreciate sudden changes of any kind, whether that be from one temperature extreme to another or a change in lighting conditions. Snow Rose should be offered plenty of light but should also have protection from the hottest summer afternoon sun, as it can be vulnerable to heat stress.
Serissa foetida does not enjoy having wet feet. The soil should be permitted to become somewhat dry before watering again. While it is sensitive to over-watering, this plant also is a good grower in winter which may cause it to need watering more than most plants do during the cool seasons. You can give it a good misting every so often, just not during flowering as it can kill the blooms prematurely. Use of a humidity tray is recommended.
Feed this bonsai every two weeks during the growing season – from spring to autumn – decreasing to monthly in the winter. You may use a good bonsai fertilizer, or a low-nitrogen time-released formula. Just be sure not to fertilize when the soil is dry, as this can cause root burn.
Snow Rose is a very versatile tree, taking well to many different styles like forest plantings, cascade, slanting, root-over-rock, and shohin. Aerial roots may form on this tree, making a potentially stunning visual effect if encouraged and trained.
New growth should be trimmed back to two sets of leaves. This can be done in the fall. Serissa loves to ramify and responds well to directional pruning. Clip and shape is usually sufficient for shaping, although wiring is possible. Don't forget to remove browned and dead blossoms so that further blooming is stimulated. Frequent trimming is necessary for this species because of its vigorous growing tendencies. It may be wired, as the branches are fairly small, but be cautious not to damage the foliage, and watch for the wires cutting into the bark due to the speed of growth.
Snow Rose is most easily propagated by cuttings. Take lengths of softwood in the spring or early summer. Harder cuttings may be taken in late summer. Bottom heat is beneficial in getting this plant to set roots.
Young Snow Rose bonsai should be repotted once a year, during the growing season (not during the winter). This plant does not like to be root-bound, hence the frequency of repotting. Older plants can tolerate waiting two or three years to be repotted. Pruning the roots will cause root suckers to grow. These should be clipped and discarded, or you can save them to use for a forest planting. Transplant the tree into a fast-draining soil mix. If you live in a dry climate, some organic matter is helpful for moisture retention.
Insects/Pests & Diseases
Like any bonsai, Serissa is susceptible to a number of pests, including aphids, scale, and mealy bugs. Aphids, which appear as tiny soft, green insects gathered in clusters on foliage, may be rinsed off in a spray of water, or alternatively you can use a spray bottle filled with dish liquid and water, then rinse with a spray bottle of plain water.
Scale appear as brownish or black bumps and must be removed with the tip of a sharp knife, or by swabbing them with rubbing alcohol. Because the eggs reside underneath this protective shell, the tree then must be treated with a mild insecticide or one specifically labeled for scale.
Following proper watering procedures and giving your Snow Rose sufficient light and air circulation will help to keep it healthy and pest free.