Origin:
Lablab purpureus (L.) Sweet subsp. bengalensis (Jacq.) Verdc. is a subspecies of the larger species Lablab purpureus, which is native to Africa. Subsp. bengalensis, specifically, is native to parts of India and Southeast Asia.
Common Names:
The plant goes by many names, including Hyacinth bean, Dolichos bean, Lablab bean, Egyptian kidney bean, Indian bean, and Seim bean.
Uses:
The Hyacinth bean plant is grown both for its edible beans and as an ornamental plant. The beans themselves are a good source of protein and can be eaten cooked or raw. They are often used in Indian cuisine and can be found in dishes such as dal and sambar. The leaves of the plant are also edible.
Beyond its culinary uses, the Hyacinth bean plant is often grown to provide shade and as a nitrogen fixer for soil enrichment. Its purple flowers and colorful pods make it an attractive addition to gardens and landscaping.
General Appearance:
The Lablab purpureus (L.) Sweet subsp. bengalensis (Jacq.) Verdc. is a climbing, twining vine that can grow up to 9 meters tall. Its leaves are trifoliate, meaning they have three leaflets, and are typically a deep green color. The plant produces vivid purple flowers and long, vibrant green or purple pods that contain the beans.
The beans themselves are flattened and oval-shaped, with a tough outer skin. Inside, they are typically a cream or white color, although some varieties may have speckles or patterns.
Light Requirements
Lablab purpureus subsp. bengalensis requires full sun exposure for optimal growth. It can tolerate partial shade, but inadequate light can lead to poor flowering and fruiting.
Temperature Requirements
The lablab bean grows well in tropical and subtropical regions where the temperatures range from 25°C to 35°C. It is sensitive to frost and cannot tolerate temperatures below 10°C. The plant grows vigorously during the warm seasons, and growth slows down during the cold seasons.
Soil Requirements
The plant prefers well-drained, friable soils with a pH range of 6.0 to 6.8. It can tolerate a wide range of soil types, including sandy or clayey soils. However, it does not grow well in waterlogged soils. The plant requires adequate moisture to perform well, and the soil should be enriched with organic matter before planting.
Cultivation methods
Lablab purpureus subsp. bengalensis is a tropical plant that grows well in warm and humid conditions. It cannot withstand frost and grows poorly in areas with extreme temperatures. The plant prefers well-drained soil with a slightly acidic pH level of between 5.5 and 6.5. It is propagated from seeds, which should be soaked in water for a few hours before planting.
Watering needs
These plants require consistent moisture for healthy growth, but overwatering should be avoided. Water the plants deeply every five to seven days if there is no rainfall. Ensure that the water reaches the roots rather than just wetting the surface. Regular monitoring of the soil will help avoid under or overwatering.
Fertilization
Lablab purpureus subsp. bengalensis requires adequate nutrition for optimal growth. Nitrogen-rich fertilizers are ideal for this plant, but excessive use of fertilizers can damage the plant. Apply a balanced fertilizer every two weeks until the plant begins to bloom, reduce the frequency to once every three weeks. Use well-decomposed organic matter, such as compost, to improve soil quality.
Pruning
Pruning is necessary to control the size and shape of the plant and to enhance its vigor. It is best to begin pruning the plant after it has reached a height of one meter to avoid stunting its growth. Cut back the plant to an appropriate height above the ground to encourage new shoot growth. Cut off any dead or diseased branches that you see, and remove any dry flowers or pods to encourage the growth of more flowers.
Propagation of Lablab purpureus subsp. bengalensis
Lablab purpureus subsp. bengalensis, commonly known as "Hyacinth Bean," can be propagated through several methods. These methods include:
Seed Propagation
The easiest and fastest way to propagate Lablab purpureus subsp. bengalensis is through seed propagation. The seeds should be collected from mature plants. Choose the best quality seeds, and soak them in water for 24 to 48 hours. Soaking the seeds will help in breaking the dormancy and hasten the germination process. After soaking the seeds, they should be sown in a nursery bed or directly in the field at a depth of 1 to 2 cm. The seeds will germinate within 7 to 10 days, and the seedlings will be ready for transplanting within 3 to 4 weeks from sowing.
Cuttings
Softwood cuttings of Lablab purpureus subsp. bengalensis can be taken during the growing season. Cuttings should be taken from healthy and disease-free plants, and the cuttings should be 4 to 5 inches long and should have two to three nodes. Dip the cuttings in rooting hormone powder and plant them in a well-draining rooting medium. Place the cuttings in a shaded area and keep them moist by regularly misting them. After four to six weeks, the cuttings will develop roots and can be transplanted to their permanent location.
Division
Lablab purpureus subsp. bengalensis can also be propagated through division. This method involves dividing the mature plants into several smaller plants with roots and shoots. The plant should be dug up, and the roots should be carefully separated using a sharp knife. Each division should have enough roots and shoots to ensure proper growth. The divided plants can then be transplanted to their permanent location and watered regularly.
In conclusion, propagating Lablab purpureus subsp. bengalensis can be done through various methods such as seed propagation, cuttings, and division. By following the proper methods, one can successfully propagate this plant for a beautiful garden or bountiful harvest.
Disease Management
Lablab purpureus subsp. bengalensis is prone to several diseases that can affect its growth and yield. Here are some of the common diseases and ways to manage them:
Anthracnose
Anthracnose is a fungal disease that causes dark, sunken lesions on leaves and stems of the Lablab purpureus subsp. bengalensis plant. It can also affect the pods and beans, resulting in reduced yield. To manage anthracnose, use disease-resistant plant varieties, remove infected plants and debris, and practice crop rotation.
Rhizoctonia Root Rot
Rhizoctonia root rot is a soilborne fungal disease that causes yellowing and wilting of leaves, stunted growth, and root rot in the Lablab purpureus subsp. bengalensis plant. To manage this disease, improve soil drainage, avoid overwatering, and use disease-free seeds. Fungicide application may also be necessary.
Powdery Mildew
Powdery mildew is a fungal disease that causes a powdery white growth on the leaves of the Lablab purpureus subsp. bengalensis plant. Severe cases can result in leaf yellowing, defoliation, and reduced yield. To manage powdery mildew, improve air circulation around the plants, avoid overhead watering, and apply fungicides as needed.
Pest Management
Aside from diseases, the Lablab purpureus subsp. bengalensis plant is also vulnerable to pest infestation. Here are some of the common pests and ways to manage them:
Aphids
Aphids are small, soft-bodied insects that suck the sap from the leaves, stems, and pods of the Lablab purpureus subsp. bengalensis plant. This can cause leaf curling, yellowing, and reduced growth. To manage aphids, use insecticidal soap, neem oil, or other organic insecticides. Introducing beneficial insects like ladybugs or lacewings can also help control aphid populations.
Cutworms
Cutworms are the larvae of night-flying moths that feed on the stems of the Lablab purpureus subsp. bengalensis plant, causing wilting and bending. To manage cutworms, apply insecticides or use physical barriers like cardboard collars around the base of the plants.
Whiteflies
Whiteflies are tiny, winged insects that feed on the underside of leaves, causing yellowing and stunted growth of the Lablab purpureus subsp. bengalensis plant. To manage whiteflies, use sticky traps or sticky barriers to reduce their numbers. Neem oil or insecticidal soap can also control whiteflies effectively.
