Yardlong Beans, Katjang Pandjang

Yardlong Bean - Vigna sesquipedalis

Introductory summary

The Yardlong Bean, also known as the asparagus bean or snake bean, is a botanical curiosity that transforms the vegetable garden into an exotic jungle. What immediately stands out is the extraordinary length of its pods: they can reach, or even exceed, 80 cm, hanging gracefully along their supports. Unlike common beans, this tropical plant loves heat and grows vigorously throughout the summer.

In terms of flavour, it is a marvel of delicacy. Harvested young, it is completely stringless, crisp, and offers a subtle taste reminiscent of asparagus and hazelnut, with a firm texture that holds perfectly when cooked. A staple of Asian cuisine, it is ideal for quick wok preparations. Growing yardlong beans means enjoying a culinary journey while cultivating a productive plant that thrives even in heatwaves. It is the perfect vegetable to diversify your harvests with originality.

Origins and botanical family

Geographical origin

This plant originates from tropical and subtropical regions, mainly West Africa and Southeast Asia, where it has been a staple food for thousands of years.

Botanical family

It belongs to the Fabaceae family (legumes), but to the genus Vigna, which biologically distinguishes it from the traditional green bean of the genus Phaseolus.

Historical notes

Very popular in China and Suriname (under the name Kousenband), it was introduced to Europe for its heat resistance and spectacular ornamental appearance.

Botanical description and characteristics

Adult height

It is a very vigorous climbing plant that easily reaches 2.5 to 4 metres in height when given proper support.

Habit

The plant has a twining habit: the stems naturally wrap around any vertical support. A tall, sturdy trellis is therefore essential.

Foliage description

The foliage is dense, composed of large, dark green, glossy trifoliate leaves that create a lush canopy.

Other morphological features

The flowers are large, often purple or yellowish, and very ornamental. They produce extremely thin, hanging pods, usually in pairs.

Sowing and cultivation conditions

Ideal sowing period

Sow late. Start indoors in warmth from April, or sow outdoors from May to June once all risk of frost has passed.

Ideal germination temperature

As a tropical plant, it requires warm soil, ideally between 20°C and 25°C, for uniform germination.

Germination time

Germination is fast under warm conditions, usually between 8 and 12 days.

Sowing depth and spacing

Sow at a depth of 2–3 cm. Space planting holes 50 cm apart and leave 80 cm between rows.

Recommended soil type

It prefers humus‑rich, well‑drained, light soil. It tolerates slightly acidic soils better than common beans.

Ideal exposure

A full sun location is crucial. It is one of the few vegetables that does not suffer from intense sunlight — quite the opposite.

Thinning

After germination outdoors, keep only the two strongest plants per planting hole to avoid competition.

Water requirements

Water regularly, especially during flowering and pod formation, to prevent the pods from becoming tough.

Care and maintenance

Pruning or pinching

Pinch the main stem once it reaches the top of its support to stimulate the production of lateral flowers.

Staking

Use strong poles, mesh, or a tipi structure. The plant becomes heavy when loaded with pods, so the support must be stable.

Disease prevention

It is fairly resistant, but watch out for black aphids that may settle on young tender stems in spring.

Harvest

Harvest period

Harvest begins about 70 to 80 days after sowing, from late July until autumn frosts.

Recognising maturity

Harvest pods when they measure 30 to 50 cm. At this size, they are tender and seedless.

Average yield

The yield is excellent. A small 3‑metre row can produce several kilos of pods over the season.

Storage method

They keep for 3 to 4 days in the refrigerator. For long‑term storage, they freeze very well after brief blanching.

Garden uses

Where to plant in the garden

Plant them on the north side of the vegetable garden to avoid shading other crops, or use them to create a green wall along a fence.

Beneficial plant associations

They pair perfectly with corn, which serves as a natural support, and with squash, which keeps the soil cool.

Crop rotation

As a legume, it fixes nitrogen in the soil. It is ideal to plant leafy vegetables (lettuce, cabbage) after it.

Culinary uses

Flavour

Its flavour is stronger than that of common green beans, with a pronounced green taste and a hint of mushroom/asparagus.

Cooking methods

Ideal cut into pieces and stir‑fried in a wok with garlic. It can also be boiled or added to spicy curries.

Tip or typical recipe

For a guaranteed visual effect, you can braid or tie the whole pods before steaming them.

Ecology, curiosities and advantages

Ecological interest

Its flowers attract pollinating insects. As a nitrogen‑fixing plant, it naturally improves soil fertility.

Anecdote

The name sesquipedalis means “one and a half feet” in Latin, referring to the impressive length of its pods.

Permaculture

It is a pillar of vertical gardening. It maximises production on minimal ground space — a major advantage in permaculture.

Why this vegetable deserves a place in the garden

The Yardlong Bean combines beauty with record productivity. It withstands very hot summers where traditional beans drop their flowers, ensuring an abundant and original harvest for lovers of exotic cuisine.