Lablab purpureus: A Brief Overview
Lablab purpureus, also known as Hyacinth bean or Dolichos bean, is a legume plant known for its edible beans and ornamental value. It belongs to the family Fabaceae and is native to Africa. The plant has been introduced to many parts of the world and is now cultivated in various countries for different purposes.
General Appearance
The Lablab purpureus plant is a fast-growing, climbing vine that can reach up to 10 meters in height. Its leaves are trifoliate, which means they are composed of three leaflets. The leaflets are broad and ovate, measuring up to 15 cm in length and width. The plant produces clusters of showy, fragrant flowers that range in color from purple to white. The flowers are followed by pods that are 10-15 cm long and contain 4-10 seeds each.
Common Names
The Lablab purpureus plant is known by several common names, including Hyacinth bean, Indian bean, Egyptian kidney bean, and Bonavist bean. In Africa, it has various names in different languages, such as njahi (Swahili), kunde (Luhya), and nyanya chungu (Chichewa).
Uses
The Lablab purpureus plant has several uses, both culinary and ornamental. Its seeds and young pods are used as a food source in many countries. In Africa, the seeds are a staple food, especially in rural areas, where they are boiled, roasted, or fermented. In Asia, the young pods are used in stir-fries and curries.
The plant is also grown as an ornamental plant in gardens and landscapes. Its showy flowers and attractive foliage make it a popular plant for trellises, arbors, and fences. In addition, the plant is used for erosion control and as a cover crop in agriculture, thanks to its ability to fix nitrogen in the soil.
Aside from its culinary and ornamental uses, the Lablab purpureus plant has medicinal properties. Its leaves, roots, and seeds are used in traditional medicine to treat various ailments, including diarrhea, diabetes, and hypertension.
Light Requirements
Lablab purpureus requires full sun to grow and thrive. It can tolerate some shade, but it may affect the plant's growth and flowering abilities. Therefore, it is essential to plant the Lablab purpureus in areas with maximum sunlight exposure.
Temperature Requirements
Lablab purpureus thrives in warm and tropical climates. The plant cannot survive in frosty or extremely cold conditions. The ideal temperature range for this plant is between 20°C to 30°C. However, it can tolerate temperature fluctuations within a reasonable limit.
Soil Requirements
The Lablab purpureus thrives in deep and well-drained soils, rich in organic matter. Soil pH should be between 6 to 7.5, which is slightly acidic to neutral. The plant requires moderate soil moisture levels, neither too wet nor too dry. Therefore, regular watering is essential, especially during dry seasons.
Cultivation Methods
Lablab purpureus, also known as hyacinth bean, is a warm-season leguminous plant that is easy to grow. It is commonly grown as a vegetable crop in Africa and Asia and as an ornamental plant in other parts of the world. The plant prefers full sun and well-drained soil with a pH of 5.5 to 7.0.
To cultivate Lablab purpureus, you can start by soaking the seeds overnight to help speed up germination. Plant the seeds 1 to 2 inches deep in the soil, spacing them 6 to 8 inches apart. The plant will grow vigorously and will need support to climb. You can provide support using trellises, stakes, or a fence.
Watering Needs
Lablab purpureus requires regular watering to thrive. Water the plant deeply but infrequently to encourage deep rooting. Ensure that the soil is well-draining to prevent waterlogging, which can cause root rot. The watering frequency will depend on the weather conditions and the soil type. In hot weather, you may need to water the plant more frequently.
Fertilization
Lablab purpureus requires regular fertilization to ensure healthy growth and maximum yield. You can apply a balanced fertilizer at planting time and another application at mid-season. The plant is also a nitrogen-fixer, which means that it can fix nitrogen from the air and convert it into a form that the plant can use. You can also grow the plant alongside other legumes to improve soil fertility naturally.
Pruning
Pruning Lablab purpureus can help improve plant growth and yield. You can remove any dead, damaged, or diseased leaves and stems to prevent the spread of diseases. The plant can also get bushy, and pruning can help promote air circulation and sunlight penetration, leading to healthier growth. You can prune the plant back in the early growing season when the plant reaches about 6 inches tall.
Propagation of Lablab purpureus
Lablab purpureus, commonly called the hyacinth bean or lablab bean, is a legume that is easy to propagate using several methods.
Seed propagation
Propagation of Lablab purpureus from seeds is the most common method. The seeds can be collected from the matured pods after the plant has flowered and fruited. The seeds must be scarified or nicked with a knife before planting to help them germinate faster.
The seeds can be sown directly into the soil or started in a nursery bed before transplanting. The ideal temperature for germination is between 20-30°C, and germination usually takes 7-14 days.
Seedlings should be transplanted when the first set of true leaves appears.
Cuttings propagation
Propagation by cuttings is also possible for Lablab purpureus. Softwood cuttings taken from the tip of the plant during the growing season can root easily in a well-draining potting mix. The cuttings should be about 6-8 inches long, and the leaves should be removed from the bottom half.
The cuttings should be dipped in a rooting hormone before planting and kept in a warm, humid location with bright, indirect light until roots develop.
Division propagation
Division propagation is another method used to propagate Lablab purpureus. Older plants can be divided into smaller sections during the dormant season using a sharp knife or spade. Each divided section should have a healthy root system and at least one growing point.
The divided sections should be planted into well-prepared soil and kept moist until signs of new growth appear.
With these propagation methods, Lablab purpureus can be easily grown and propagated in many areas.
Disease Management
Lablab purpureus, also known as hyacinth bean or dolichos bean, is susceptible to various diseases that can stunt growth or cause yield losses. Among the common diseases that affect the plant include:
- Anthracnose - It is a fungal infection that causes irregular, sunken spots on leaves, stems, and pods. It can also cause blight and premature defoliation in severe cases.
- Bacterial blight - It is a bacterial disease that causes dark green water-soaked spots on leaves, stems, and pods, which later turn brown and crispy. It can also cause stem rot and seedling death in severe cases.
- Mosaic virus - It is a viral infection that causes stunted growth, yellow-green or dark green mottling of leaves, and distorted pods. It can also reduce yields in severe cases.
To manage these diseases, farmers can apply fungicides or bactericides as soon as they notice the symptoms. Also, they can remove and destroy dead or infected plant parts to prevent the spread of the disease. Maintaining crop rotation, planting disease-resistant varieties, and ensuring proper drainage can also help to prevent disease infestations.
Pest Management
Lablab purpureus is also prone to pest infestations that can cause damage to the leaves, stems, and pods. Some of the common pests of the plant include:
- Aphids - These are small, pear-shaped insects that suck sap from the leaves and stems, causing curling, yellowing, and stunted growth. They can also transmit viral diseases.
- Pod borers - These are caterpillars that bore into the pods, causing fruit drop and yield losses. They are usually active during the fruiting period.
- Cutworms - These are soil-dwelling larvae that cut the seedlings at the base, causing plants to wilt and die.
To manage these pests, farmers can use insecticides or biological control methods, such as introducing natural enemies that feed on the pests. Also, they can practice good cultural practices, such as removing crop debris, using clean seeds, and maintaining proper soil fertility, to minimize pest infestations.
