Origin
Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro is a deciduous tree that is native to Africa. The tree commonly grows in the savannah and dry woodland regions of Africa, from Senegal to Ethiopia and down to South Africa.
Common Names
The plant is commonly known by several local names, including Marula, Maroela, Amantungulu, Ingqakamfana, and Umganu.
Uses
Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro is a culturally significant plant in Africa. Different parts of the tree have been used by indigenous people for various purposes, including medicine, food, and cosmetics. The bark and roots are used to treat several ailments such as dysentery, diarrhea, and stomach pains. The leaves and fruits are rich in vitamin C and are used to make traditional African beer, juice, and jam. The seeds produce an oil that is used in cosmetics and cooking. The Marula oil has numerous health benefits, including anti-inflammatory and antioxidant properties.
General Appearance
The Marula tree can grow up to 18 meters tall and has a single trunk, with a broad, spreading, and rounded crown. The tree has grayish-brown, fissured bark, and its leaves are deciduous, alternate, and simple. The leaves are oval-shaped, with a leathery texture that is light green in color. The Marula tree blooms from September to November, producing small, fragrant, white, or cream flowers. The fruit is approximately the size of a small plum, with a hard, woody, stone-like kernel at the center, surrounded by a yellowish-green, fleshy pulp that is sweet and tart in flavor.
Light Requirements
The Sclerocarya birrea subsp. caffra typically thrives in areas with full sunlight exposure. It requires a minimum of six hours of direct sunlight to grow optimally. Hence, the plant should be located in an open expanse with minimal obstruction or shading from tall trees or buildings.
Temperature Requirements
The plant prefers warm and dry climates, where the temperature range should be between 25 to 30 degrees Celsius. It can still grow in cooler temperatures, but its growth and fruiting are typically delayed. Avoid exposing the plant to frost, which can severely damage the leaves and stem or kill the plant altogether.
Soil Requirements
The Sclerocarya birrea subsp. caffra thrives best in well-drained soils that have a loamy texture and a pH range of 5.5 to 7.5. The soil should be able to retain moisture effectively while still allowing free drainage. The plant is relatively drought-tolerant, but it cannot survive in waterlogged or swampy soil. To achieve optimal growth, consider adding organic matter like compost into the soil to enrich its nutrient composition.
Cultivation Methods for Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro
Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro, commonly known as the Marula tree, is a generally hardy species that can grow in diverse environments. It prefers well-drained soils that range from sandy to loamy textures, with pH levels from 5.2 to 8.2. It is also highly drought-tolerant, although it will benefit from regular watering during its early growth stages.
The seeds of Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro can be directly sown in the field or grown in containers for later transplantation. Since the Marula tree has a deep root system, it is recommended to provide a large planting hole to accommodate the roots.
The tree can be propagated through seeds or vegetative methods such as air-layering and cuttings. However, seedlings are the most preferable since they have a more extensive root system that helps the tree to establish better and faster.
Watering Needs
Although Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro is highly tolerant of drought, frequent watering during the early stages of growth is essential. After the tree is established, it still benefits from regular watering, especially during dry spells. Watering should be done at the base of the tree rather than overhead to prevent fungal infections. Avoid overwatering since this can lead to root rot.
Fertilization
Marula trees do not require much fertilizer since they can scavenge nutrients from the soil quickly. However, the application of organic matter to the soil can enhance tree growth and yield. A balanced fertilizer containing nitrogen, phosphorus, and potassium can be applied in moderate amounts during the growing season. Do not apply fertilizers during the dormant period.
Pruning
Pruning Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro trees is not necessary, but it can enhance their overall look and increase productivity. Pruning should be done during the dormant period or immediately after harvesting. Cut off any branches that are diseased, broken, or dead. To promote more fruiting wood, remove old branches and those that are growing sideways or crossing each other. Pruning should be done moderately to avoid causing damage to the tree.
Propagation of Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro
Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro can be propagated by both sexual and asexual methods, including seed propagation, cuttings, and grafting.
Seed propagation
The plant produces large fruits containing a single seed enclosed in a hard shell. To propagate Sclerocarya birrea by seeds, the seeds must be extracted from the fruit and sown immediately in well-draining soil. Pre-soaking the seeds in water for 24 hours before planting can enhance germination rates.
It is recommended to plant the seeds in a nursery or seedbed, where the seedlings can be protected from harsh weather conditions. In a nursery, the seedlings can be left to grow until they reach about 30 centimeters in height before being transplanted into their permanent locations in the field.
Cuttings
Propagation by cuttings involves taking a part of the plant, usually a stem, rooting it and growing it into a new plant. This method is usually used for selected cultivars or plants with desirable traits. Cuttings should be taken from mature plants during their dormant period, which is preferably in winter.
To propagate Sclerocarya birrea by cuttings, select healthy branches of about 15 to 30 centimeters long and 0.5 to 2.5 centimeters in diameter. The cuttings should be stripped of their leaves and planted in a rooting medium. Application of rooting hormone may enhance rooting success rates.
Grafting
Grafting involves taking vegetative parts of one plant and attaching them to another plant to form a union between the two, which will eventually grow as one plant. This method is mainly used for propagating species or cultivars that are difficult to propagate by other methods.
Sclerocarya birrea can be propagated by grafting onto rootstocks of the same species or closely related species. The best time for grafting is in late winter or early spring before the onset of the growing season, when both the scion and rootstock are in a dormant state.
Disease and Pest Management for Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro
Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro, commonly known as the Marula tree, is a native flora of Southern Africa. Though it is known to survive under harsh environmental conditions, it is still susceptible to certain pests and diseases.
Common Pests
African bollworms (Helicoverpa armigera) are known to infest young fruits, causing severe damage to the yield. Integrated pest management strategies can help tackle this pest. For instance, the use of pheromone traps, crop rotation, and intercropping with repellant plants like lemongrass, marigold, and garlic can help to deter African bollworms from attacking Marula trees.
Scales (Lepidosaphes) can also be a menace to Marula trees. Inspect trees regularly to detect the presence of scales. To manage this pest, use horticultural oil sprays, insecticides, and release biological controls like parasitic wasps.
Common Diseases
Anthracnose is a fungal disease that affects the leaves, stems, and fruits of Marula trees. It is identified by small reddish-brown spots that appear on the leaves and fruits. Applying copper-based fungicides on the tree can help manage Anthracnose.
Root Rot is a bacterial disease that affects Marula trees in waterlogged soil. This condition can ultimately lead to tree death. To prevent root rot, avoid planting Marula trees in waterlogged soils, and ensure adequate soil drainage.
Powdery mildew is a fungal infection that appears as a powdery white coating on the leaves and stems of a Marula tree. To manage powdery mildew, prune affected plant parts, apply fungicides, and ensure proper air circulation around the tree canopy.
Conclusion
Effective disease and pest management strategies can help to maintain healthy Marula trees. It is recommended to carry out regular inspections and implement measures to prevent the occurrence of pests and diseases. Integrated pest management techniques and appropriate use of fungicides and insecticides can assist in the management of pests and diseases of Marula trees.
