Overview
Pterocelastrus rostratus (Thunb.) Walp., also known as bird's eye root or isiZulu (Zulu language) as umahlabaza, is a perennial shrub that belongs to the family Celastraceae. This plant is native to Southeastern Africa, where it is found in countries such as South Africa, Eswatini, Zimbabwe, and Mozambique.
Appearance
Pterocelastrus rostratus is a multi-stemmed shrub that can grow up to 2 to 3 meters high. It has a spreading, bushy habit with a dense crown. Its leaves are glossy, dark green, leathery and elliptic to ovate in shape. The plant's bark is grey to pale brown, fibrous, and peels off in flakes, revealing a smooth surface beneath.
Common Uses
In traditional medicine, the roots of Pterocelastrus rostratus are used to treat various ailments such as fever, rheumatism, arthritis, constipation, diarrhea, and dysentery. The plant is also used as a natural insecticide, and its crushed leaves are applied to wounds to promote healing. Additionally, it serves as a source of firewood, fence posts, and construction materials.
P. rostratus is an attractive ornamental plant. In gardens and landscapes, it is used to provide shade, erosion control, and hedge boundaries. It is easy to grow and can tolerate a wide range of soil types and climatic conditions.
Light Requirements
Pterocelastrus rostratus grows best in partial to full shade conditions. Direct sunlight can cause leaf scorch and stunted growth. It is often found growing under the canopy of taller trees, where it receives dappled sunlight.
Temperature Requirements
This plant can tolerate a wide range of temperatures, but it prefers warm and humid conditions. Temperatures between 18-24°C (65-75°F) are ideal. In colder regions, it can survive mild frosts but may lose its leaves. In hot and dry conditions, it will need more frequent watering.
Soil Requirements
Pterocelastrus rostratus prefers well-draining, acidic to neutral soil. It can tolerate a wide range of soil types, but it must not be waterlogged. The soil should be enriched with organic matter, like peat moss or compost, to retain moisture and provide nutrients.
Cultivation Methods
Pterocelastrus rostratus is a low-maintenance plant that is suitable for both indoor and outdoor cultivation. It thrives in well-drained soils with a pH range of 5.5 to 7.0. The plant prefers partial shade to full sun, and it can tolerate light frost.
The ideal temperature range for the plant growth is between 18°C to 25°C. The plant can suffer from root rot if the soil is not well-draining or if overwatered. Therefore, it’s crucial to practice proper watering methods and provide appropriate drainage for the plant.
Watering needs
The watering needs of Pterocelastrus rostratus are moderate. It’s important to keep the soil evenly moist but not waterlogged. Overwatering can lead to root rot, and underwatering can lead to plant stress and wilting.
Water the plant deeply once per week, but reduce frequency during winter months. Check the soil moisture level by sticking your finger about an inch into the soil. If the soil feels dry, it’s time to water.
Fertilization
Fertilize the Pterocelastrus rostratus plant once a month with a balanced liquid fertilizer solution. During the growing season, use a fertilizer that’s high in nitrogen to promote foliage growth. During winter months, use a fertilizer that’s high in phosphorous to promote flowering.
Avoid fertilizing the plant during its dormant period, as this can lead to fertilizer burn. Read the label instructions and apply the fertilizer as directed.
Pruning
Pterocelastrus rostratus requires minimal pruning, but it can benefit from occasional removal of dead or damaged foliage. Pruning can be done anytime throughout the year, but avoid pruning during the onset of winter.
To promote bushiness and fuller growth, pinch back the tips of the plant stems. This will encourage the plant to branch out and produce more foliage. Use pruning shears to cut back any overgrown or leggy stems to keep the plant compact and tidy.
Propagation of Pterocelastrus rostratus
Pterocelastrus rostratus (Thunb.) Walp. can be propagated either through sexual or asexual methods.
Sexual Propagation
The plant produces small flowers that usually appear from May to June. The flowers are hermaphroditic, meaning they have both male and female reproductive organs. The plant is known to be self-fertile, which means that it can produce seeds without the need for cross-pollination. The seeds are small, brown, and shiny, measuring approximately 4-6 mm in length. They are enclosed in a woody capsule that is about 10-12 mm in diameter. The seeds require stratification to germinate, which is the process of exposing them to a specific temperature and moisture conditions to break their dormancy. It is recommended to stratify the seeds for six weeks at a temperature of 4°C before planting.
Asexual Propagation
Asexual propagation can be done through various methods such as stem cuttings, layering, and grafting.
Stem Cuttings
Stem cuttings are taken from mature, healthy plants during the growing season. The cuttings should be approximately 10-15 cm long and have at least two nodes. The leaves on the lower half of the cutting should be removed, and the cutting should be dipped in rooting hormone before planting. The cutting should be planted in a well-draining potting mix and kept in a warm and humid environment. The cutting should root in about six to eight weeks.
Layering
Layering is a method in which a branch is bent to the ground, and a section of it is buried in the soil, leaving the tip exposed. The buried section will develop roots, and once rooted, it can be cut from the parent plant and transplanted into a new pot or planted directly into the ground.
Grafting
Grafting involves taking a scion from a mature plant and attaching it to the rootstock of a related species. The rootstock is selected for its vigor and disease resistance, and the scion is selected for its desirable characteristics such as flower color or fruit size. The two plants are joined together using a grafting tape or clip, and once they have fused, the plant can be transplanted.
Common Diseases
There are several diseases that can affect Pterocelastrus rostratus, including:
- Anthracnose: This fungal disease can cause leaf spots, defoliation, and twig dieback. It can be managed by pruning infected twigs and branches and applying fungicides.
- Powdery mildew: This fungal disease can cause a white powdery growth on leaves and stems, eventually leading to leaf drop. It can be managed by removing infected plant parts and applying fungicides.
- Root rot: This disease is caused by fungi that attack the roots and can cause wilting and yellowing of leaves. It can be managed by improving drainage and using fungicides.
Common Pests
Some of the common pests that can affect Pterocelastrus rostratus are:
- Scale insects: These pests suck sap from the leaves and stems, causing yellowing and leaf drop. They can be managed by manually removing them or using insecticides.
- Caterpillars: These pests can chew on leaves and cause defoliation. They can be managed by manually removing them or using insecticides.
- Spider mites: These pests are not insects but can cause damage to the plant by sucking sap from the leaves. They can be managed by increasing humidity and using insecticidal soaps.
Management Strategies
The following are some strategies to manage diseases and pests on Pterocelastrus rostratus:
- Prune: Regular pruning can help remove infected plant parts and improve air circulation.
- Improve drainage: Ensuring good drainage can prevent root rot and other soil-borne diseases.
- Remove pests manually: Some pests can be removed by hand, such as scale insects and caterpillars.
- Use insecticides and fungicides: Chemicals can be used to control pests and diseases, but should be used as a last resort and according to instructions.
- Encourage natural predators: Beneficial insects such as ladybugs and lacewings can help control pests.
