Yardlong Bean.

At a glance

Care level

Easy

Plant type

Annual vegetable

Light

Full sun

Indoor light

Direct sun

Water

Every 2 to 4 days

Mature size

3 to 4 meters

Growth rate

Fast

Hardiness

USDA 9 to 11

Bloom time

Mid to late summer

Care

Provide a strong trellis for the vines to climb as they grow quite tall. Watch for wilting leaves which indicate the plant needs more water during hot spells. Keep an eye out for aphids on the tender new growth.

Watering

Keep the soil consistently moist but not waterlogged to ensure the best pod production.

Feeding

Apply a balanced vegetable fertilizer every few weeks once the plant begins to flower.

Pruning

Trim back excessive side shoots if the plant becomes too crowded to improve airflow.

Repotting

These are annuals and are typically grown directly in the garden soil.

Soil

Well draining loamy soil

Soil pH

6.0 to 7.0

Temperature

15 to 35°C

Humidity

40 to 70%

Safety

People

The raw seeds contain compounds that can cause digestive distress if consumed in large quantities.

Children

The seeds are small and pose a choking hazard to young children.

Contact allergens

The foliage can cause mild skin irritation in sensitive individuals.

Airborne allergens

Pollen may trigger mild reactions in those with legume allergies.

Edibility

Always cook the beans thoroughly before eating to neutralize lectins.

How to identify it

• Extremely long slender green pods
• Vining growth habit
• Trifoliate bright green leaves
• Small pale yellow or purple flowers

Height

2 to 4m

Spread

0.3 to 0.6m

Leaves

green, deciduous

Flowers

white, yellow, purple, 1 to 2cm

Fruit

green, yellow, brown, Late summer to autumn

Problems to watch for

• AphidsCommon
• Root RotCommon
• Mexican Bean BeetleUncommon
• Pod BorerUncommon
• Powdery MildewUncommon
• ThripsUncommon

Growing it

Propagation

seed

When to plant

spring, early summer

Plant cowpeas alongside corn to maximize space and improve soil fertility simultaneously.

Grows well with

• Corn · Corn provides a natural trellis for the cowpea vines to climb.
• Cucumber · Cowpeas provide nitrogen to the soil which benefits heavy feeders like cucumbers.

Keep away from

• Onion · Onions may inhibit the growth of legumes when planted in close proximity.

Similar species

• Mung bean · Shares similar growth habits and environmental requirements.
• Adzuki bean · Another member of the Vigna genus with similar cultural needs.

Science

Family

Fabaceae

Genus

Vigna

Order

Fabales

Class

Magnoliopsida

Native range

Central and West Africa

Conservation

Not of conservation concern as it is a widely cultivated agricultural crop.

This plant survives in hot, arid environments by developing a deep root system and maturing quickly.

Value to wildlife

nectar source, nitrogen fixer

Pollinators

bees, butterflies

Uses

culinary, cover crop, forage

Taxonomy resolved against GBIF.

Questions people ask

Can I grow cowpeas in a container?

Yes, they grow well in large pots with adequate drainage.

When should I harvest the pods?

For fresh eating, harvest the pods while they are young, slender and tender, before the seeds swell, or wait until they dry for storage.

Where the name comes from

The genus name Vigna honors the Italian botanist Domenico Vigna, while unguiculata refers to the claw-like shape of the flower petals.

Good to know

• Cowpeas are not actually peas but are more closely related to mung beans.
• They are a staple ingredient in the Southern United States dish known as Hoppin' John.
• The plants enrich the soil by fixing nitrogen from the air.
• They thrive in hot weather where other beans might fail.