The natal plum is a beautiful tropical shrub. Like Indian hawthorn, it is used frequently in commercial landscapes. Its pretty white flowers are star-shaped and fragrant and produce edible red fruit. However, only the fruit is edible; the rest of the plant is toxic.
|Botanical Name||Carissa macrocarpa|
|Common Name||Natal plum, big num-num, Amatungulu or grootnoem-noem|
|Mature Size||2 to 8 feet, but can grow to 20 feet depending on variety|
|Sun Exposure||Full to partial sun|
|Native Area||South Africa|
For best results, plant natal plum in sandy soil that drains well, as this will help naturally deter root rot. If you have grown a specific variety and wish to have more plants, propagate new plants from cuttings to ensure all of the plants have the same characteristics. If you have a regular species of shrub, you can collect and plant the seeds from the mature plants.
This shrub does have sharp spines, so it can work well as a barrier or hedge. You can shape natal plum into a tree form or hedge through pruning. Trimming will also prompt the shrub to produce more flowers and fruit. You may need to prune plants that are close to a sidewalk so that pedestrians do not get stuck by the spines.
Natal plum has ovate leaves that are dark green with a glossy sheen. They are usually 1 to 3 inches long and are formed along the branch in an opposite arrangement. If you have smelled orange blossoms, you know what natal plum flowers smell like. The two plants have very similar scents. Each flower features five waxy petals arranged in a star shape.
You can eat the red fruit fresh or make it into jams, pies, tarts, syrups, pickles, sauces, or jellies. They will be bitter with lots of latex if eaten while unripe.
Grow natal plum in a location that receives full sun for the best results. It will also do fine in part sun but will likely not have as many flowers and fruits.
Water monthly to weekly depending on the variety, but be careful not to overwater as Natal plum is susceptible to root rot. Good drainage is very important; an easy way to do this is to place the pot on elevated pebbles. Natal plum is drought tolerant.
The Natal plum thrives in temperatures that range above 68 degrees Fahrenheit during the day and between 50 and 65 degrees at night. Natal plum does need a moister environment, and you can use a moisture tray under the plant to maintain humidity (being sure that the roots are not kept in the water). Another option is to mist your plants several times a week. It must be brought indoors in winter in colder climates; to keep it fungus-free, you will need to run a fan nearby.
Use a fertilizer that has equal parts of nitrogen, phosphorus, and potassium. This will help maintain the shrub's general health and promote fruiting.
It's best to transplant Natal plums in winter or fall, avoiding root pruning. Repot into fast-draining soil, and avoid overwatering.
Natal plum is easy to propagate using stem cuttings which can be taken at any time of the year. Select 4–6-inch cuttings, treat them with rooting hormone, and either insert them in moist sand or place them in a glass of water. Once the roots appear, plant the stems in compost that consists of one part sand, one part peat moss, and two parts loam. Keep the new Natal plums moist (not wet), and provide bottom heat with a heating pad.
There are three common varieties of Carissa macrocarpa, of which Natal plum is the largest. Emerald Blanket is a dwarf cultivar. It is a low, spreading plant that is often used as a ground cover shrub.
If you want a small variety that is two feet tall or under, look for Nana, Prostrata, Bonsai, Boxwood Beauty, or Horizontalis. Nana and Boxwood Beauty also have the advantage of no thorns. Boxwood Beauty is a smaller, mounded shrub that is often used as a foundation planting or ground cover.
You should not have many pest problems with this shrub. You may see Florida red scale (Chrysomphalus aonidum) or aphids, which can be removed with horticultural soap. Fungal infestation may occur if Natal plum is overwatered.
Be cautious when planting natal plum in a household with pets or children. The fruit is the only part of the plant that is not poisonous.