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Vigna spp.

cowpeas and relatives

Fabaceae

Tropical and subtropical Africa and Asia

Attracts Pollinators Attracts Butterflies Drought Tolerant

SunFull Sun

WaterMedium · drought-tolerant

Overview

Vigna is a genus of roughly 100 species of annual and perennial legumes in the pea family, distributed across the tropics and subtropics of Africa, Asia, and the Americas. Several species are major food crops, including cowpea (V. unguiculata), mung bean (V. radiata), adzuki bean (V. angularis), and the yardlong bean (V. unguiculata ssp. sesquipedalis). Habit ranges from erect bushy plants 1 to 3 feet (30 to 90 cm) tall to twining climbers reaching 6 to 10 feet (1.8 to 3 m) on support. Leaves are alternate and trifoliate, with three broad leaflets. The pea-type flowers are 0.5 to 1.2 inches (1.5 to 3 cm) wide in yellow, purple, pink, or white, and are followed by slender cylindrical pods 3 to 36 inches (8 to 90 cm) long depending on species. All species are frost-tender and grow during warm weather, dying at the first frost. As legumes, they fix atmospheric nitrogen through root nodules, but young growth is palatable to aphids and bean beetles.

Native Range

Vigna occurs naturally across tropical and subtropical Africa and Asia, with the greatest species diversity in Africa, the center of origin of cowpea. A smaller number of species are native to tropical America. Cultivated species are now grown throughout warm regions worldwide.

Suggested Uses

Grown chiefly as food crops for their edible pods, dried pulses, and sprouts, and as cover crops or green manure that adds nitrogen to the soil. Bushy types are grown in vegetable rows; climbing types are trained on trellises and fences. Some species double as forage for livestock.

How to Identify

Recognized by alternate, trifoliate leaves with three entire leaflets and twining or erect herbaceous stems. The pea-family flowers have the typical keel-and-wing structure, often with a coiled or asymmetric keel that distinguishes Vigna from the closely related genus Phaseolus. Pods are narrow, cylindrical, and many-seeded, splitting along two sutures when ripe.

Appearance

Size & Dimensions

Height1' - 10'

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Summer

Flowering occurs through the warm season, mainly June to September in temperate cultivation and year-round in the tropics. Plants flower 6 to 8 weeks after sowing and continue producing flowers and pods until frost or the end of the growing season. Individual flowers are short-lived, often opening and fading within a day.

Detailed Descriptions

Flower Description

yellow, purple, pink, or white

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

loam sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Seed is sown directly in warm soil above 65 F (18 C) in full sun, as germination and growth stall in cold conditions. Most species need consistent moisture during flowering and pod fill but tolerate short dry spells once established. Soil of moderate fertility is sufficient, since the plants fix their own nitrogen; heavy nitrogen feeding produces leafy growth at the expense of pods. Climbing types are supported on a trellis, fence, or poles 6 to 8 feet (1.8 to 2.4 m) tall. Aphids, bean beetles, and root-knot nematodes are the main pests. Regular pod harvest prolongs production.

Pruning

Pruning is limited to pinching the growing tips of climbing types to encourage branching and to keep vines within their support. Dead and frost-killed growth is cleared at the end of the season. No woody pruning applies.