Hyacinth bean is a fast-growing vine grown in American gardens for its purple flowers and flat purple pods. It comes from tropical Africa and is grown as a food crop across the tropics, but in most of the US it's an ornamental annual for trellises and fences. The raw mature beans are poisonous unless thoroughly boiled.
Appearance
- Growth form
- A twining vine that can reach 10–20 ft (3–6 m) on a sturdy support.
- Leaves
- Each leaf has three broad, pointed leaflets about 2–6 in (5–15 cm) long, green or purplish, with short hairs underneath.
- Flowers
- Fragrant pea-like flowers in white, pink, or purple, held on upright spikes 3–6 in (8–15 cm) long. They bloom from summer into fall.
- Fruit
- Flat, smooth, pointed pods 2–4 in (5–10 cm) long, often bright purple, ripening in fall. Each usually holds two to five seeds.
Look-alikes
Where it lives
- Typical habitats
- gardens
- trellises and fences
- farm fields in the tropics
- Range
- Native to tropical Africa and India, though its exact homeland is uncertain, and now grown throughout the tropics. In the US it's a garden plant, not a native wildflower.
- Preferred conditions
- Loves heat and humidity. Needs full sun and light, moist, well-drained soil. Hardy only in USDA zones 10–11, so elsewhere it's grown as an annual.
Growing it
- Care
- Sow seed outdoors after the danger of frost has passed. Selections with white flowers or dark burgundy leaves are also grown.
- Propagation
- Grown from seed. Seed color varies by variety: white, cream, brown, red, black, or mottled.
- Toxicity
- The beans contain compounds that release cyanide. Mature dried beans are edible only after thorough boiling with several changes of water; eating large amounts raw can cause vomiting, labored breathing, twitching, and convulsions.
Name and classification
- About the name
- Formerly called Dolichos lablab. Botanists recognize two cultivated subspecies (purpureus and bengalensis) and one wild subspecies (uncinatus) from Africa.
Culture and stories
- Culture and stories
- Around the world it goes by many names, including lablab bean, bonavist bean, Egyptian kidney bean, and Indian bean.
- It has been cultivated in India since ancient times, and young pods and beans are used in South Asian, Southeast Asian, East Asian, and East African cooking.
- Farmers in warm regions grow it as livestock forage and to enrich soil, since its roots host .
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