Carissa edulis (Forssk.) Vahl var. tomentosa (A.Rich.) Stapf
Commonly known as the Natal plum, Carissa edulis (Forssk.) Vahl var. tomentosa (A.Rich.) Stapf is a slow-growing, evergreen shrub that is native to southern Africa. The plant belongs to the Apocynaceae family which also includes popular plants such as the oleander and frangipani.
General Appearance
The Natal plum typically grows to a height of about 2 to 3 meters and spreads to 2 to 3 meters in width. The shrub has an upright growth habit with glossy and dark green leaves that are about 3–6 cm long. The leaves are leathery, stiff, and closely spaced on the branches. The plant also has sharp spines that can grow up to 3 cm long along the branches. Natal plums bloom small, white, and fragrant flowers that eventually develop into edible, red-tinged plum-shaped berries that are about 2 to 4 cm long and have a tart flavor.
Uses
The Natal plum has a variety of uses, both ornamental and practical. Its attractive glossy foliage, fragrant flowers, and colorful fruits make it a valuable garden plant for hedges, borders, and ground covers. The plant is also used for soil erosion control due to its dense root system and ability to grow in poor soil conditions. The Natal plum fruit is edible and can be eaten fresh or incorporated into desserts, jams, and jellies. In traditional medicine, various parts of the plant are used to treat wounds, diarrhoea, and stomach ailments.
Light conditions
Carissa edulis var. tomentosa prefers bright and direct sunlight. They can tolerate partial shade, but the plant may not thrive in low light conditions. Therefore, it is advised to grow them in a location that receives a minimum of 4 hours of direct sunlight.
Temperature requirements
The ideal temperature range for the growth of Carissa edulis var. tomentosa is between 20-30°C (68-86°F). They can tolerate higher temperatures up to 40°C (104°F) but can suffer in freezing temperatures. Therefore, it is essential to protect them from frost and cold winds.
Soil requirements
Carissa edulis var. tomentosa can grow in a variety of soils, ranging from sandy to loamy or clayey. However, they prefer well-draining soil that is rich in organic matter. The soil pH should be neutral to slightly acidic, ranging from 6 to 7.5. It is recommended to amend the soil with compost or organic matter to improve its fertility and texture.
Cultivation Methods
Carissa edulis (Forssk.) Vahl var. tomentosa (A.Rich.) Stapf is commonly known as the Natal plum. It is relatively easy to grow and can thrive in different soil types such as sandy, loamy, or clay soils. For the cultivation of this plant, it is essential to provide it with adequate sunlight and well-draining soil. Natal plum is a sub-tropical plant that can tolerate a wide range of temperatures. It is ideal to grow this plant in a greenhouse or in a warm location.Watering Needs
Natal plum requires moderate watering, especially during the growing season. The soil should be kept moist but not waterlogged. During hot dry spells, it is essential to water the plant to prevent water stress. Young plants require more frequent watering, but adult plants can withstand dry spells.Fertilization
The Natal plum is an evergreen plant that requires regular fertilization to promote healthy growth and fruit production. It is best to apply a balanced fertilizer once every month during the growing season. The use of organic fertilizers such as fish emulsion or compost can be beneficial for the plant's growth.Pruning
Pruning is an essential cultivation practice that helps to maintain the plant's shape and promote fruit production. Natal plum can be pruned lightly anytime during the year to remove dead, damaged or diseased stems. The best time to do a more significant pruning would be in the early spring before the growing season starts. Pruning of the Natal plum should be done with sharp, clean tools to avoid damaging the stem.Propagation of Carissa edulis var. tomentosa
Carissa edulis var. tomentosa, also known as the Desert Num-Num or Amatungulu, is a hardy evergreen shrub that is native to semiarid regions of southern Africa. This plant is widely cultivated for use as a hedge, barrier or garden ornamental. Here are some propagation methods that can be used to multiply the Carissa edulis var. tomentosa:
Seed propagation
Seeds are the most common means of propagating Carissa edulis var. tomentosa. This method is best done in early spring, ensuring a success rate of 70-80%. Seeds should be sown in a mixture of coarse river sand and compost and placed in a warm, well-lit area. Soil temperature should ideally be between 20°C -30°C. Germination generally takes place within 3-4 weeks. After germination, the mixture should be watered regularly and thinned out after 2-3 months.
Cuttings propagation
Carissa edulis var.tomentosa can also be propagated by cuttings from young or tender stems. Cuttings should be taken from a healthy plant, measuring 7-10cm in length, and planted in a rooting hormone. The cutting should then be placed in a soil mixture of river sand and compost and placed in the shade. Water the soil in moderation, to avoid excess water and rotting the cutting. Rooting usually occurs after 4-5 weeks.
Division propagation
Carissa edulis var.tomentosa can occasionally be propagated by division. This is done by taking a cutting from the original plant and carefully separating the roots, as the plant grows large enough. The divided plantlets should be planted in a well-drained sandy soil, and watered regularly. This method should be done in autumn, and the plant should be given ample time to establish itself before the onset of winter.
Disease Management
Carissa edulis (Forssk.) Vahl var. tomentosa (A.Rich.) Stapf is generally a resilient plant that does not suffer from frequent and severe diseases. However, under certain conditions, the plant may be susceptible to some diseases and infections. Here are some common diseases that might affect the plant and suggestions to manage them:
- Crown rot : Crown rot is the most common disease affecting Carissa edulis. It is caused by a soil-borne fungus that infects the roots and progresses upward, causing decay and discoloration of stems, leaves and eventually the entire plant. On detection of signs of crown rot, remove the infected plant parts and stop watering to avoid the spread of funguses via water. Chemical fumigation may help kill the fungus and prevent re-infection of the plant roots.
- Leaf Spot : Leaf spot is a fungal disease characterized by brown or black spots on the leaves and stems, causing leaf drop and reduced plant vigor. On the detection of signs of leaf spot, remove and destroy all infected plant parts. Also, ensure the plant has proper air circulation, adequate light, and is not watered overhead or late in the day.
- Root Rot : Root rot is caused by waterlogged soil, which leads to root decay and a fungal or bacterial infection. To prevent root rot, make sure the plant is grown in well-draining soil and is not watered too frequently. Additionally, avoid over-fertilization of the plant, which can lead to salt accumulation and root damage.
Pest Management
Although Carissa edulis is generally not susceptible to pests, some common pests that can attack the plant include:
- Mealybugs : Mealybugs are sap-sucking pests that appear as whitish, cottony masses on the plant's stems and leaves. To manage a mealybug infestation, remove the affected parts of the plant and wash it with a mild soap solution. Additionally, you can introduce natural predators like ladybugs, lacewings or parasitic wasps that feed on mealybugs.
- Scale Insects: Scale insects appear as small, brown bumps on the stems and leaves of the plant. They suck the plant sap, causing leaf yellowing, stunted growth and eventually death. To manage a scale infestation, scrub the affected areas with a toothbrush dipped in rubbing alcohol or insecticidal soap. Reapplication may occur every two weeks until there are no more scales present.
- Spider Mites : Spider mites appear as tiny, reddish-brown spots on the leaves of the plant. They suck the plant sap, which causes the plant to turn yellow or brown and eventually die. To manage a spider mite infestation, regularly mist the plant with water to increase humidity levels, remove affected leaves, and apply insecticidal soap.
Always remember to regularly check your Carissa edulis (Forssk.) Vahl var. tomentosa (A.Rich.) Stapf plants for any signs of diseases or pests. Early detection is key to managing, preventing and minimizing any damage.
