Origin
Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt, commonly called the forest false-thorn or wild laburnum, is a species of flowering plants in the family Fabaceae. The species is native to sub-Saharan Africa, ranging from Angola and Namibia in the southwest to Tanzania in the northeast.
Common Names
The plant is commonly known by a range of names including forest false-thorn, wild laburnum, African laburnum, and hairy calpurnia. The name "laburnum" is also used because of the similarity of the plant's flowers to those of the Laburnum anagyroides tree species; however, the two plants are actually unrelated.
Appearance
Calpurnia aurea subspecies sylvatica is a deciduous or semi-evergreen shrub or small tree that can reach up to 10 meters in height. The plant has a single stem and a rounded to spreading crown, with a dense bushy growth habit. The bark is dark grey and rough, while the branches are slender and flexible, often with spines or thorns. The plant has compound leaves that are trifoliate, with each leaflet being oblong to elliptical in shape and up to 10 cm long. The leaves are light to green and hairy on the undersides.
The plant's flowers are bright yellow and appear in large clusters in spring to early summer, with some sporadic flowering throughout the year. The flowers are eventually replaced by seed pods that are flat and up to 13 cm long. The seed pods contain several brown or black seeds that are surrounded by a brown, papery covering.
Uses
Calpurnia aurea subspecies sylvatica is a versatile plant that has a range of uses in traditional and modern medicine. The plant's bark, roots, and leaves contain various bioactive compounds such as alkaloids, flavonoids, and tannins that have been used to treat a range of ailments. The plant has been used to treat wounds, skin infections, fevers, and digestive disorders.
The plant also has several non-medicinal uses. The plant's wood is hard and has been used for making furniture, tool handles, and fencing. The plant is also used as a live fence as it is thorny and can grow densely, making it difficult for livestock and wildlife to pass through. Additionally, the plant is used in landscaping as an ornamental plant due to its attractive yellow flowers and bushy growth habit.
Growth Conditions of Calpurnia aurea subsp. sylvatica
Light: Calpurnia aurea subsp. sylvatica require full sun to partial shade to grow. They thrive in open areas where they can receive direct sunlight for at least eight hours a day.
Temperature: The ideal temperature for the growth of Calpurnia aurea subsp. sylvatica ranges between 20°C and 30°C. These plants are moderately frost tolerant and can withstand brief periods of frost.
Soil: Calpurnia aurea subsp. sylvatica prefer well-drained, fertile soils that are slightly acidic to neutral (pH 5.5 to 7.0). They grow well in sandy, loamy or gravelly soils that are rich in organic matter. These plants have low tolerance to waterlogged conditions and heavy clay soils.
Water: Calpurnia aurea subsp. sylvatica require moderate watering. They should be watered deeply at least once a week during dry seasons to promote healthy growth. Overwatering can lead to soil saturation, which can cause root rot and other diseases.
Fertilizer: These plants do not require regular fertilization, but they respond well to occasional feeding with a balanced fertilizer that contains nitrogen, phosphorus, and potassium. Fertilizer application should be done during the growing season.
Propagation: Calpurnia aurea subsp. sylvatica can be propagated through seed or cuttings. Seeds should be sown in well-drained soil in autumn or spring, while softwood cuttings should be taken in summer and hardwood cuttings in autumn. Propagation through division is also possible.
Cultivation
Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt is a shrub that typically grows in well-drained soils. It thrives in sunny to partially shaded environments, making it an ideal choice for gardens and landscaping projects. When planting, ensure the soil is mixed with compost or other nutrients to support the initial growth of the plant.
Watering needs
Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt requires consistent watering, especially during the early years of growth. The plant should be regularly watered until it becomes established and can tolerate drought. However, it is important not to overwater the plant, as this can lead to root rot and other diseases.
Fertilization
The plant benefits from regular fertilization to encourage healthy growth and blooming. Fertilizer should be applied during the growing season, and the frequency and amount will depend on the soil quality and the age of the plant. Consider using a balanced fertilizer with a ratio of 10-10-10 or similar to support the plant's needs.
Pruning
Routine pruning is necessary to keep Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt in good shape. It is best to prune during the dormant season, which is typically in late winter or early spring. Cut back any dead wood or damaged branches. Also, remove any crossing or rubbing branches to prevent damage and improve air circulation within the plant.
Propagation of Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt
Calpurnia aurea (Aiton) Benth. subsp. sylvatica (Burch.) Brummitt, commonly known as wild laburnum, can be propagated through seed and vegetative methods.
Propagation by seeds
The seeds of Calpurnia aurea can be directly sown in the field or in pots filled with a mixture of sand and compost in a 1:1 ratio. The seeds should be sown at a depth of 1-2 cm and covered lightly with soil. Germination usually occurs within 2-4 weeks.
Before sowing the seeds, they must first be scarified by soaking them in hot water for 12-24 hours or by nicking the seed coat with a sharp knife to facilitate water absorption. This is because the hard seed coat of Calpurnia aurea prevents water from entering the seed and delaying germination.
Propagation by stem cuttings
Calpurnia aurea can also be propagated vegetatively using stem cuttings. This method is useful for preserving the desirable characteristics of a particular cultivar. Softwood cuttings should be taken from the current season's growth during late spring to early summer.
The cuttings should be about 10-15 cm long, with at least two nodes. Remove the leaves from the lower one-third of the cutting, dip the cut end in rooting hormone powder and plant it in a pot filled with a well-draining rooting medium such as perlite or vermiculite.
The pot should then be covered with a plastic bag to create a humid environment and placed in a shaded area. Keep the soil moist but not waterlogged, and the cuttings should form roots within 4-6 weeks.
Disease and Pest Management for Calpurnia aurea subsp. sylvatica
Calpurnia aurea subsp. sylvatica is a bushy shrub that grows up to 4 m tall. It is native to southern Africa and is used in traditional medicine. The plant is generally healthy, but it can be affected by a few pests and diseases. Here's a look at some of the common ones and ways to manage them.
Diseases
Leaf Spot: One of the most common diseases that affect Calpurnia aurea subsp. sylvatica is leaf spot. This is a fungal disease that causes small yellow or brown spots on the leaves. The spots can grow bigger and merge, causing the leaves to die and fall off. To manage this disease, remove and destroy all infected leaves and stems and avoid overhead watering. If the problem persists, apply a fungicide that contains copper or chlorothalonil.
Root Rot: Calpurnia aurea subsp. sylvatica is susceptible to root rot, especially when grown in poorly drained soil. This disease is caused by a fungus that attacks the roots, making them brown and mushy. The plant may wilt, and its leaves may turn yellow. To manage root rot, improve drainage and avoid overwatering. Destroy any infected plant material and apply a fungicide that contains thiophanate-methyl.
Pests
Aphids: Aphids can be a problem for Calpurnia aurea subsp. sylvatica. These small insects feed on the sap of the plant, causing leaves to curl and become distorted. They also excrete a sugary substance called honeydew, which can attract ants and promote the growth of sooty mold. To manage aphids, spray the plant with a strong jet of water to dislodge them. You can also apply insecticidal soap or neem oil.
Scale Insects: Scale insects are another pest that can affect Calpurnia aurea subsp. sylvatica. They are small, oval-shaped insects that attach themselves to the stems and leaves of the plant, feeding on its sap. They secrete a waxy substance that can make them hard to detect. To manage scale insects, prune and destroy infected plant material and apply horticultural oil to smother the insects.
Caterpillars: Caterpillars can also be a problem for Calpurnia aurea subsp. sylvatica. These larvae feed on the leaves of the plant, causing defoliation. To manage caterpillars, remove them immediately by handpicking or applying Bacillus thuringiensis (BT) to the leaves. BT is a natural bacterium that is toxic to the larvae but harmless to people and pets.
By following these management practices, you can keep your Calpurnia aurea subsp. sylvatica healthy and free of pests and diseases.
