An evergreen, small thorny bush which develops white and pink flowers and edible, dark red fruit. There is little information on this plant in the bonsai literature, which is surprising, as it is readily available and becoming quite popular. In addition, Natal plum is a strong plant which tolerates almost any abuse. It can be grown under almost any conditions (except freezing cold), but when grown under optimum conditions of high heat and humidity, growth is extremely rapid and the rooting of cuttings an almost sure success.
Likes plenty of light, at least four hours of direct sunlight daily.
Needs warmth in winter. Prefers night temperatures between 50-65F and day temperatures of 68F or higher. Can successfully be grown indoors, but the use of a nearby fan to reduce the likelihood of fungal infestation is recommended.
Moderate. When grown indoors, use of a moisture tray to maintain humidity is recommended.
Every two weeks during growth, using Miracid. Reduce feeding to monthly during winter.
Do major pruning in mid to late spring, after flowering. Do not prune all the green foliage off a branch, as this will cause the branch to die back. Otherwise, buds back with vigour. Continue to prune as necessary during growth. Carissa grows rapidly, especially in hot climates, so pruning may be frequent. These trees make good informal uprights or cascades. Older branches can be brittle, so use caution when wiring. Check wiring often, due to the rapid growth of the plant.
Roots readily from cuttings, especially lignified ones. Will root when placed in a glass of water.
Lesniewicz recommends transplanting in fall or winter only, but posters to RAB indicated that repotting in mid-spring to midsummer is OK. Keep root pruning to a minimum. Use fast draining soil. Limit water until the plant is firmly established to reduce risk of root rot.
Prone to fungal infestation. Spider mites and scale are occasional problems. On the whole, a very strong plant.
Carissa grandiflora: Natal plum.
Carissa macrocarpa: Natal plum, Christ’s thorn.
Compiled by Sabrina Caine