The evergreen flowering plum (Carissa grandiflora) is also known as the Natal-plum and common carissa. The plant is a member of the dogbane family, the same family as showy aster, baneberry, mountain buttercup, prickly-pear cactus, catnip, clover and catnip. The plant has a limited growing area in the United States, but gardeners in other areas grow the flowering plum as a patio plant in containers and bring the plant in for the winter.
The plant grows from 6 to 20 feet tall and 4 to 10 feet wide. The egg-shaped, dark-green, evergreen leaves measure 2 to 4 inches long. Fragrant, white, star-shaped flowers bloom heavily in the summer and less frequently throughout the rest of the year. The flowers are followed by red, edible, plum-shaped berries from 1 to 3 inches long, oftentimes staying on the bush until the next crop of flowers appears.
Natal-plum likes full sun or partial shade--at least 4 hours of sun a day--and clay, loam or sandy, well-drained moist to dry soil. Night temperatures between 50 and 65 degrees F and daytime temperatures of at least 68 degrees F are necessary for the plant to reach its full potential.
The plant is a native of South Africa and is hardy in USDA Plant Hardiness Zones 9 to 11. It is a relatively fast growing shrub that is popular along the coastlines of Florida and California because of its ability to withstand salt water and strong winds.
The plant can be grown from seeds. However, more often it is done by taking stem cuttings from 4 to 6 inches long and using growth hormone in moist sand with heat rising from under the container.
The berries have a cranberry-like taste and jam can be made from them. The bush is used in making bonsai, as a foundation plant, in groups to form a privacy screen, as a ground cover or in a flower garden border. Natal-plum works well in a container or in a raised planter.
Over-watering causes root-rot. Insects do not cause a major problem and the plant is generally not bothered by diseases. The plant has large, forked thorns and can damage skin. All parts of the plant are poisonous, with the exception of the fruit, but it is only safe when fully ripe.