Vigna unguiculata aka Cowpea

Vigna unguiculata, or cowpea, belongs to the bean family, Fabaceae. Its native range covers Cape Verde and tropical and southern Africa. It grows in tropical regions with a dry season. Farmers also grow it across warm parts of the world. Cowpea is an annual, so it completes its life cycle within one year. It grows fast and can scramble or climb by twining.

Garden plants reach about 5–10 feet (1.5–3.05 metres) tall. Their spread is about 1–3 feet (0.3–0.91 metres). Green leaves grow in an alternate pattern along the stems. Each compound leaf has several leaflets rather than one blade. The leaves feel thin and papery, and the plant has hairs. Its stems have no scent. This leafy growth gives the plant value as cover for wildlife.

Cowpea blooms in summer, with showy purple or lavender flowers. The flowers have an uneven shape and form clusters called cymes. Each flower measures less than 0.08 feet (0.025 metres) across. The fruit is a seed pod, classed as a legume. People eat the young pods before they fully mature. They also harvest the seeds for use as dried beans. The species serves as a vegetable crop in edible gardens. Growers use its foliage as feed for livestock.

Cowpea grows best in full sun and needs soil that drains well. It accepts sandy, loamy, and clay soils, including poor soils. A slightly acid soil, around pH 5.5–6.5, suits it best. Seeds need warm soil to germinate. Gardeners sow it in spring for a summer cover crop. It tolerates drought but also grows in moist soil. It cannot withstand frost, flooded ground, or soil that stays waterlogged. Its fast growth helps shade out weeds during summer. It also fixes nitrogen and helps improve soil fertility.

Cowpea needs little upkeep under suitable growing conditions. Its flowers add interest, while its growth can provide screening. The plant also offers food and shelter for wildlife. Hot, humid weather can bring powdery mildew. Aphids and plant hoppers may attack the crop. Root-knot nematodes are another concern, though resistance varies among cultivated forms. Plants that set seed may leave unwanted seedlings behind. Edible pods and seeds do not establish safety for every plant part. The supplied species-level sources give no broader toxicity assessment.