Plant Description:
Rinorea angustifolia (Thouars) Baill. subsp. natalensis (Engl.) Grey-Wilson is a small to medium-sized tree that belongs to the Violaceae family. The tree is characterized by a thin trunk, reaching a height of up to 15 meters, and produces a wide, low branching crown that can span up to 5 meters wide.
Origin:
The plant is a native of the eastern and southern regions of Africa. It can be found in countries such as Ethiopia, Kenya, Tanzania, Uganda, Zimbabwe, and South Africa. It is commonly found in forests, woodlands, and riverine vegetation in high rainfall areas at altitudes ranging from 550 to 2500 meters above sea level.
Common Names:
The plant is commonly known as the "Natal Rinorea" in English. In Swahili, it is known as "Mkoko" or "M'koko," while in Afrikaans, it is called "Natalese Rinore."
Uses:
The plant has several traditional uses which ranges from medicinal to cultural purposes. The roots, leaves, and bark of the plant are used to treat various ailments such as fever, stomach problems, respiratory diseases, and general body pains. The bark and leaves are also used as an insect repellent. The wood of the plant is used for making small carvings and is also suitable for fuel and charcoal production. The plant is also significant culturally, and it is believed that certain rituals performed using Rinorea angustifolia can have spiritual or divinatory powers.
General Appearance:
The leaves are simple, alternate, and narrowly elliptic or oblong-lanceolate, growing to about 8-29cm long and 2-7cm wide, with a pointed base and a tip that tapers to a point. The leaves are usually shiny and dark green on the upper surface and paler beneath. Flowers are small, white, tubular, and occur in clusters at the end of branches. The fruits are small capsules that contain seeds.
Growth Conditions of Rinorea angustifolia subsp. natalensis
Rinorea angustifolia subsp. natalensis is a plant species that is native to South Africa and typically grows in forested areas. It is a hardy, evergreen shrub or small tree that has a slow growth rate and can reach up to 5 meters in height.
Light Requirements
Rinorea angustifolia subsp. natalensis prefers partial shade to full sun exposure. It can tolerate a wide range of light conditions but does best when grown in bright, indirect light.
Temperature Requirements
Rinorea angustifolia subsp. natalensis thrives in a warm, humid environment. It prefers temperatures between 20-25^oC but can tolerate temperatures as low as 10^oC.
Soil Requirements
Rinorea angustifolia subsp. natalensis grows best in well-draining, fertile soil. It prefers slightly acidic to neutral soil with a pH range of 5.5-7.5. Adding organic matter to the soil can help improve its quality and increase its moisture-holding capacity.
Cultivation methods
Rinorea angustifolia subsp. natalensis can be grown in containers or in the ground. It prefers partial shade to full shade and well-draining soil. The soil should be rich in organic matter and have a pH level of 6.0 to 7.5. The plant can tolerate low temperatures up to about -5°C and can also handle high humidity levels.
Watering needs
Rinorea angustifolia subsp. natalensis prefers moderate watering. The soil should be kept slightly moist but not waterlogged. The plant can withstand short periods of drought, but overwatering can cause root rot.
Fertilization
Rinorea angustifolia subsp. natalensis benefits from regular fertilization. A balanced, slow-release fertilizer can be applied every three months during the growing season. Alternatively, a liquid fertilizer can be applied once a month. Over-fertilization can cause excessive growth and reduce the plant's overall health.
Pruning
Pruning is not necessary for Rinorea angustifolia subsp. natalensis, but it can be done to maintain its shape and size. Any dead or diseased branches should be removed promptly. The plant can also be lightly pruned after flowering to encourage bushier growth.
Propagation of Rinorea angustifolia subsp. natalensis
Rinorea angustifolia subsp. natalensis can be propagated through different methods, including seeds and stem cuttings.
Propagation through Seeds
The seeds of Rinorea angustifolia subsp. natalensis should be collected from mature fruits. After collection, the seeds can be stored in a cool and dry place until needed for propagation. Prior to planting, the seeds can be soaked in water for 24 hours to improve germination rates.
For planting, a well-draining potting mix can be used. The seeds should be planted at a depth of 1-2 cm and covered with a layer of soil. Water the soil well and maintain moist soil conditions until the seeds germinate, which can take up to 4-6 weeks.
Propagation through Stem Cuttings
Stem cuttings can also be used to propagate Rinorea angustifolia subsp. natalensis. The cuttings should be taken from mature stems during the growing season and should be at least 10 cm long with two or three leaf nodes. The lower leaves should be removed, leaving only two or three leaves at the top of the cutting.
The cuttings can then be treated with a rooting hormone and planted in a well-draining potting mix. The cuttings should be planted at a depth of 2-4 cm and covered with a plastic bag to maintain humidity levels. Keep the soil moist and ensure that the cuttings are not exposed to direct sunlight. After about 4-6 weeks, the cuttings should start producing roots and new leaves, indicating successful propagation.
Disease Management
Like most plants, Rinorea angustifolia subsp. natalensis is susceptible to a range of diseases that can impact growth and appearance. Below are some common diseases and ways to manage them:
Leaf Spot
Leaf spots are fungal diseases that appear as small brown or black spots on the leaves. They can cause leaves to yellow and eventually fall off the plant. To manage leaf spot, remove infected leaves and destroy them. Apply copper-based fungicides to protect uninfected leaves. Ensure that the plant is not overcrowded, and avoid overhead watering.
Anthracnose
Anthracnose is a fungal disease that causes brown or black spots on the leaves. It can cause the leaves to become distorted and fall off the plant. To manage anthracnose, remove infected plant parts, destroy them, and apply copper-based fungicides to protect uninfected plant parts. Avoid overhead watering and ensure the plant is not overcrowded.
Powdery Mildew
Powdery mildew is a fungal disease that appears as a white powdery substance on the leaves. It can cause leaves to curl and eventually fall off the plant. To manage powdery mildew, remove infected leaves and destroy them. Apply sulfur-based or neem oil-based fungicides to protect uninfected leaves. Ensure the plant is well-ventilated, and avoid overhead watering.
Pest Management
Pests can also be a problem for Rinorea angustifolia subsp. natalensis. Below are some common pests and ways to manage them:
Aphids
Aphids are small sap-sucking insects that can cause leaves to curl and become distorted. To manage aphids, use a strong jet of water to wash them off the leaves. Alternatively, apply insecticidal soap or neem oil-based insecticides.
Caterpillars
Caterpillars are the larval stage of moths and butterflies that can cause severe damage to the plant. They can chew through leaves, stems and even flowers. To manage caterpillars, physically remove them from the plant or apply Bacillus thuringiensis-based insecticides.
Scale insects
Scale insects are small, immobile insects that secrete a protective coating and can damage the plant by sucking on sap. To manage scale insects, use a soft-bristled brush or cotton swab dipped in rubbing alcohol to remove them from the plant. Repeat the process until the scales are completely removed.
