Overview
Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan, commonly known as Flat Top Albizia, is a tree species that belongs to the Fabaceae family. It is native to southern Africa and is known for its versatility in various areas of use.
General Appearance
The Albizia petersiana subspecies can grow up to 15 meters in height, with a round crown and a smooth grey-brown bark. The leaves are alternate, bipinnately compound, with each leaf having between 6 to 16 pairs of pinnae. Each pinna has between 20 to 30 pairs of bright green leaflets that are narrow and elongated, measuring between 5 to 10 mm in length. The flowers are fragrant, creamy-white, and numerous, with each flower measuring between 35-50 mm in length. The subspecies Albizia petersiana evansii has a flat-topped crown that differentiates it from the main species.
Common Names
The Albizia petersiana species has numerous local common names, including Flat Top Albizia, White Siris, African Siris, and Butterfly Tree. The subspecies evansii is also known as Large Flat Top Albizia or Evans' Albizia.
Uses
The Albizia petersiana species and its subspecies are versatile in their uses. The tree's wood is soft, light, and easy to work with, making it ideal for carving and making furniture, fuel, and charcoal. The bark of the tree has medicinal properties and has traditionally been used to treat fevers, rheumatism, and stomach problems. In South Africa, the subspecies evansii is used for soil stabilization and soil improvement, as it acts as a nitrogen fixer. The subspecies is also planted for shade and ornamental purposes in gardens, parks, and along roadsides. In addition, the tree attracts butterflies and bees, which helps in pollination.
Light Requirements
Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan requires full sun to partial shade for optimal growth. This species is more tolerant of shady conditions than other Albizia species.
Temperature Requirements
Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan thrives in warm to hot temperatures. Although this species can tolerate temperatures as low as 10 degrees Celsius, it grows best in temperatures ranging from 20 to 35 degrees Celsius.
Soil Requirements
This species thrives in well-draining soils that are rich in organic matter. Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan can tolerate a wide range of soil types, from sandy to clayey soils, but it grows best in loamy soils. The soil pH should be acidic to neutral, ranging from 5.0 to 7.0.
Cultivation
Albizia petersiana subsp. evansii is a tree that can grow up to 15 meters tall and 8 meters wide. It is native to southern Africa and can grow in a range of soil types, including sand, loam, and clay. The tree prefers full sunlight to partial shade and thrives in moist, well-drained soil. It is hardy and can tolerate drought, but it requires regular watering for optimal growth.
Watering
When cultivating Albizia petersiana subsp. evansii, it is important to maintain an even level of moisture in the soil. Watering should be done regularly, especially during dry periods, and should not be overdone to avoid waterlogging. The frequency of watering depends on the soil type, temperature, and humidity levels. However, it is advisable to let the soil dry out slightly between watering sessions.
Fertilization
Albizia petersiana subsp. evansii requires fertilization to thrive. You can use a general-purpose fertilizer with a balanced N-P-K ratio, such as a 10-10-10 or 20-20-20 formula. Fertilization should be done during the active growing season, which is usually between spring and fall. Avoid fertilizing during the winter months when the tree is dormant. Over-fertilization can cause damage to the tree and soil, so follow the manufacturer's instructions carefully.
Pruning
Pruning is essential when cultivating Albizia petersiana subsp. evansii. It helps maintain the tree's shape, prevents the branches from breaking, and improves flowering and fruiting. The best time to prune is during the winter months when the tree is dormant. Remove any dead, diseased, or damaged wood. You can also prune to thin out crowded branches, encourage new growth, or shape the tree. Avoid excessive pruning, as it can weaken the tree and reduce its overall health.
Propagation of Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan
Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan can be propagated both sexually and asexually. Here are some of the methods:
Sexual Propagation
Propagation from seeds is the most common method of sexual propagation of Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan. Seeds are collected from healthy and mature trees during the fruiting season, which is usually from March to April. The seeds should be stored in a cool, dry place until they are ready to be sown. Before sowing, the seeds should be soaked in warm water for 24 hours to soften the hard seed coat. Sowing can be done in trays or seedbeds filled with sandy loam soil. The seeds should be sown shallowly and covered with a layer of soil. Germination usually occurs within two to three weeks. The seedlings can be transplanted to polybags or containers when they are about 6-8 weeks old.
Asexual Propagation
Asexual propagation of Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan can be done using different methods, including:
- Cuttings: Stem cuttings can be taken from mature, healthy trees during the dormant season, which is usually from June to August. The cuttings should be about 15-20 cm in length, with 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 powder before being inserted into a rooting medium, such as sand or perlite. The cuttings should be kept in a humid environment with diffuse light until they develop roots, which usually takes about four to eight weeks. After rooting, the cuttings can be transplanted to polybags or containers.
- Air layering: Air layering is another method of asexual propagation of Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan. It involves removing a ring of bark from a mature branch, applying rooting hormone to the exposed wood, and wrapping it with moist sphagnum moss and plastic wrap. Roots will form at the site of the bark removal, and when they are well-developed, the rooted branch can be cut off from the parent plant and transplanted to a new location.
- Grafting: Grafting is a method of asexual propagation where a scion of the desired plant variety is joined together with a compatible rootstock. Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan can be grafted onto the rootstock of other Albizia species. This method is usually done by experienced horticulturists and is not commonly used for propagation of Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan.
Disease and Pest Management for Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan
Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan, commonly known as Flatcrown, is a medium-sized tree that is native to southern Africa. This tree species is relatively resistant to pests and diseases, but it can still be affected by some common issues that should be managed appropriately to avoid significant damage to the plant.
Common Diseases
Anthracnose: Anthracnose is a fungal disease that can infect the leaves, stems, and fruits of the Flatcrown tree. Symptoms include small, circular, brown spots on leaves that may merge and result in defoliation. In severe cases, the tree may experience stunted growth and decreased vigor. Bordeaux mixture or copper-based fungicides can be used to manage this disease effectively.
Root rot: Root rot is a soil-borne disease caused by several fungal pathogens that can infect the roots of the Flatcrown tree. Symptoms include wilting, yellowing or browning of leaves, leaf drop, and a general decline in the tree's overall appearance. Precautions like planting the tree in well-draining soil and avoiding overwatering can help prevent this disease. If root rot does occur, affected plants should be removed and destroyed, and the soil should be treated with fungicides.
Common Pests
Aphids: Aphids are small, sap-sucking insects that can infest the Flatcrown tree's leaves and stems. Symptoms of an infestation include yellowing, stunted growth, and honeydew secretion. Control can be achieved using cultural methods like removing affected leaves and encouraging natural predators or using insecticidal soap and neem oil to kill the aphids.
Borers: Flatcrown trees can also attract several species of borers that can cause significant damage to the tree's health. Signs of infestation include sawdust-like frass near the tree's bark and entry and exit holes. Regularly monitoring the tree and removing infected branches can help control borers. However, serious infestations may require professional intervention.
Spider mites: Spider mites are tiny arachnids that feed on the Flatcrown tree's leaves, causing leaf stippling, discoloration, and defoliation in severe cases. Spraying the tree with a strong blast of water or using chemical insecticides can help manage spider mites effectively.
It is crucial to have a proactive approach in managing pests and diseases in Albizia petersiana (Bolle) Oliv. subsp. evansii (Burtt Davy) Brenan. Continuous monitoring and periodic preventive measures like fertilization, pruning, and watering can help prevent and manage many issues that this tree species might experience.
