The South African bonsai tree is a member of the genus Mesembryanthemaceae, or Mesembs. It is a cactus from one of the largest succulent families and produces a caudex, or thickened trunk, which stores moisture for the plant. Reproduction can be accomplished from cuttings or from seed, although cuttings are easier and quicker to establish. Seed can be ordered at most cacti and succulent shops and clubs.
Trichodiadema bulbosum is the scientific name for South African bonsai. The plant is a succulent cactus with long branches and gray leaves with thin, white thorns. Its lavender or white flower blooms in summer and grows three-fourths of an inch long. The cactus is from South Africa and is drought tolerant. South African bonsai forms a small shrub with an underground caudex, or thickened root structure. The caudex rises out of the soil as the plant gets older, giving the appearance of a thickened trunk.
The caudex is fibrous root material that stores moisture for the plant. It hardens and solidifies on the exterior when exposed to air, much like bark on a tree. Several caudiciforms are considered succulent and make excellent bonsai forms. The caudex on the South African bonsai can grow to nearly 12 inches in diameter.
South African bonsai prefers well-drained soil and full sun. The soil can be sand to sandy loam and should have a pH range of 5.5 to 6.5. Too much water will cause the plant's caudex to mildew or rot. The bonsai should not be watered in the summer. Mesembs come from areas with little organic matter, so the soil can be fairly sterile, and the plants need little fertilizer.
Mesembs are easily grown and cultivated, and the South African bonsai is no exception. The seed can be planted in either spring or fall. Germination is rapid, generally only taking 10 days to two weeks for the first sprouts to appear. The little plants grow quickly and can reach twice their original size in a couple of weeks. After a month, the plants are drought tolerant and are fully grown within two years. Flowers can be produced in a year.
As the plant grows older its caudex becomes more evident, and the cactus will assume the shape of a bonsai. It can be repotted to expose more of the caudex and pruned and wired just like a bonsai. If it is grown as a bonsai, the growth will cluster at the top of the plant, giving it more of an appearance of a little tree. South African bonsai grows from 19-to-24 inches tall in a bonsai pot.