Both the rainbow bush and the elephant bush are a type of Portulacaria afra. The rainbow bush is a variegated version of the plant. Both bushes originate from South Africa and can reach 4 to 6 feet in height. They are small shrubs with tiny round leaves that are thick and fleshy. They are quite easy to care for.
Since the bushes are very drought tolerant and do not fare well in a soggy environment, use a potting soil that is loose and drains well. A general purpose formula that is high quality will generally be sufficient. If the soil does not drain well enough, mix peat moss or any other organic compost in to help.
Water the bushes regularly with enough water to cause drainage from the bottom of the pot. Allow the soil to dry out a little bit before watering again. Warm water is recommended for watering, and rainwater should be used with caution as it may be acidic.
Feed the bushes with a water soluble fertilizer. This should be done twice a year, once in April and again in July. Keep the bushes in a sunny location that will receive full sun or only a small amount of shade. Sun that comes from the south or west is the best.
Both the rainbow and the elephant bush are suitable for bonsai planting. In USDA zones 10a to 11 they can be grown outdoors as long as night temperatures do not drop below 40 degrees F.
The bushes are prone to mealy bugs. Any new plants that are brought into the home should be thoroughly inspected for pests. Treat infested plants by pruning infected branches and spraying the plants with a solution of 90 percent water and 10 percent rubbing alcohol. Repeat the treatment weekly until all signs of infestation are gone. There are also insecticide soaps available in garden centers and nurseries. Any plants that are heavily infested may need to be destroyed if treatment is unsuccessful.
Both bushes are easily propagated by taking cuttings from a healthy adult plant. Remove a section of a branch that is 4 to 6 inches in length. Place the cutting in a warm dry area and allow the cut end to callous over. Once the end has hardened, plant the cutting in coarse sand or soil mixed with peat moss and water well. Keep the cutting in an area that has bright, indirect lighting. Roots will begin to appear in six to eight weeks.