Overview
Tabernaemontana usambarensis K.Schum. ex Engl. is an evergreen shrub or small tree belonging to the family Apocynaceae. It is native to East Africa, particularly found in the Usambara and Uluguru Mountains of Tanzania and Kenya.
Common Names
The plant is commonly known as Usambara or African-gardenia, East African Tabernaemontana, and African-teak.
Description
The Tabernaemontana usambarensis is a small tree or large shrub that can grow up to 6 meters in height. It has a dense and bushy crown, with a straight trunk up to 30 cm in diameter. The bark is grey and smooth when young, while the mature trees have a rough and flaking bark. The leaves are glossy and dark green, around 8-13 cm long and 3-6 cm wide. The flowers are white with a sweet fragrance, around 2 cm in diameter, and bloom in clusters from late summer to early winter. The fruit is a woody capsule that splits open when mature to release numerous seeds that are dispersed by the wind.
Uses
The Tabernaemontana usambarensis plant has diverse uses in traditional medicine. In Tanzania, the roots and leaves are used to treat various ailments, including fever, malaria, headache, and abdominal pain. The plant extract has also been used to manage hypertension, inflammation, and bacterial infections. The wood is hard and durable, making it suitable for carving, furniture making, and construction. The plant is also used in landscaping as an ornamental plant due to its attractive foliage and flowers.
Light Requirements
The Tabernaemontana usambarensis K.Schum. ex Engl. plant requires a full sun or partial shade for proper growth. It can thrive under direct sunlight, but it must be sheltered from hot, scorching rays during the hottest parts of the day.
Temperature Requirements
The plant can grow well in warm temperatures, between 18 to 30 degrees Celsius, but it cannot tolerate frost or freezing temperatures. It is essential to protect it from cold winds and frost, especially during the winter season.
Soil Requirements
The Tabernaemontana usambarensis K.Schum. ex Engl. grows well in loose, well-draining soil that has good moisture retention capacity. The soil should be rich in organic matter and nutrients, and the pH should be slightly acidic to neutral, ranging from 6.0 to 7.5.
The plant requires regular watering, especially during the growing season, but it cannot tolerate waterlogging or standing water around its roots. Mulching the soil can help retain moisture and improve soil fertility.
Cultivation Methods
Tabernaemontana usambarensis K.Schum. ex Engl. is a beautiful plant that thrives well in warm temperatures and bright light. As a tropical plant, it requires a lot of humidity. Therefore, you should consider planting it in a humid environment or use a humidifier. It also grows best in well-drained soils that are rich in organic matter like humus or compost. The plant can be propagated from cuttings or seeds.
Watering Needs
The watering needs for Tabernaemontana usambarensis K.Schum. ex Engl. depends on the type of soil and the growing conditions. Overwatering can cause the roots to rot, so you should allow the soil to dry out slightly between waterings. However, when watering, make sure that the soil is moist but not waterlogged. Avoid watering the leaves to prevent the development of fungal diseases.
Fertilization
Tabernaemontana usambarensis K.Schum. ex Engl. requires a balanced fertilizer that includes both macronutrients and micronutrients. Fertilize the plant once every two weeks during the growing season using a water-soluble fertilizer. In winter, reduce fertilization to once a month. Make sure to follow the package's instructions and avoid over-fertilization, which can cause leaf burn or death.
Pruning
Pruning Tabernaemontana usambarensis K.Schum. ex Engl. helps to control its size and promote branching. Pruning should be done in early spring before the growing season. Start by removing dead or damaged branches and then prune back the remaining branches to encourage new growth. Do not prune aggressively as this can cause stress to the plant. You can also pinch back the tips of the plant to make it bushier.
Propagation of Tabernaemontana usambarensis K.Schum. ex Engl.
Tabernaemontana usambarensis K.Schum. ex Engl. can be propagated through various methods which include:
Seeds
Seeds can be collected from ripe capsules, cleaned and sown in seedbeds. The seeds should be sown immediately after collection and should be covered with a thin layer of soil. They should then be watered and placed in a shade house or under shade cloth. The germination period is usually two to four weeks. The seedlings can be transplanted to individual pots when they are big enough to handle.
Cuttings
Cuttings taken from semi-hardwood are also a viable method of propagating Tabernaemontana usambarensis K.Schum. ex Engl. Cuttings should be taken from the current season's growth, and should be about 10-15cm long. The cutting should be treated with rooting hormone and inserted into a well-draining mix of sand and compost. The cuttings should be kept moist and placed in a shaded area. The roots should develop within 6-8 weeks, and the cuttings can then be transplanted to individual pots.
Air layering
Air layering is another method used to propagate Tabernaemontana usambarensis K.Schum. ex Engl. This method involves making a small cut on a healthy stem, dusting it with rooting hormone and then wrapping damp sphagnum moss around the cut section. The moss should be wrapped in plastic wrap and secured with a rubber band. Roots should develop within 2-3 months, and the rooted section should then be cut from the parent plant and potted up.
Division
Division is a method used for mature plants. The plant is carefully dug up and divided into smaller sections. Each section should have a good root system and a healthy stem. Each section can then be potted up separately.
Disease Management for Tabernaemontana usambarensis K.Schum. ex Engl.
Like many plants, Tabernaemontana usambarensis K.Schum. ex Engl. is vulnerable to several diseases. Some of the common diseases that might affect the plant include:
- Powdery mildew: This appears as white or gray powder-like spots on the leaves of the plant. To manage this disease, remove the infected parts and increase air circulation by pruning crowded areas.
- Leaf spots: This is common in wet and humid climates and is characterized by brown to black spots on the leaves. To manage this, use of fungicides such as copper-based or sulfur-based ones, and also prune infected parts to promote air circulation..
- Root and stem rot: This is a fungal disease that causes the plant to wilt, and in worse cases it results in the death of the plant. To manage this disease, ensure that the plant is not being overwatered, improve the drainage, and use fungicides such as copper-based ones.
Pest Management for Tabernaemontana usambarensis K.Schum. ex Engl.
Tabernaemontana usambarensis K.Schum. ex Engl. is also vulnerable to attack from several pests. Some of the common pests that might affect the plant include:
- Mealybugs: These are small white insects that suck the sap from the plant, and they are usually found on the leaves. To manage this pest, remove the insects by hand, and use insecticides specifically formulated for mealybugs.
- Scale insects: These are small insects that feed on the plant sap, and they appear as small bumps on the leaves and stems. To manage this pest, use a soft-bristled brush to remove the insects, and also use insecticides such as neem oil.
- Spider mites: These are small insects that usually affect the undersides of the leaves of the plant, and they cause yellow or brown spots. To manage this pest, remove the affected parts and use of a miticide.
- Fungal gnats: They are small flying insects that are usually seen around the plant and their larvae feed on the roots of the plant hence causing the death of the plant. To manage this pest, allow the soil to dry out between watering and use of insecticides specifically formulated for these pests.
Proper sanitation practices are also important in disease and pest management. Always clean the area around the plant, remove any fallen leaves, and avoid overwatering the plant.
