Yardlong bean Vigna unguiculata subsp. sesquipedalis
Yardlong bean (Vigna unguiculata subsp. sesquipedalis) is an annual vegetable in the Fabaceae family, native to Cultivar group of cowpea (African origin), selected in tropical Asia. It grows 2–4 m (6.6–13 ft) tall and 30–50 cm (12–20 in) wide, wants full sun and moderate water, and is hardy to about 5 °C (41 °F). Space plants about 30 cm (12 in) apart.
Plan Yardlong bean in your garden →
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Yardlong bean at a glance
| Type | Annual vegetable |
|---|---|
| Family | Fabaceae |
| Mature height | 2–4 m (6.6–13 ft) |
| Mature spread | 30–50 cm (12–20 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Moderate; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5.5–7 |
| Cold hardiness | About 5 °C (41 °F) once established (roughly USDA zone 11) |
| Heat stress | Likely above about 36 °C (97 °F) |
| Flowering | about 6–8 weeks after planting, for 9–13 weeks |
| Days to maturity | About 80 days from planting |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Yes: young pods (cooked), young leaves, mature seeds (cooked) |
| Native to | Cultivar group of cowpea (African origin), selected in tropical Asia |
| Common in gardens of | 🇹🇭 Thailand, 🇨🇳 China, 🇸🇬 Singapore, 🇮🇩 Indonesia, 🇲🇾 Malaysia |
Is Yardlong bean toxic?
- People: mildly toxic
- Cats: not well documented
- Dogs: not well documented
- Parts: raw pods, raw seeds
Raw beans contain lectins and trypsin inhibitors that upset the stomach; cook before eating.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Yardlong bean
Good neighbours
- good With Sweet corn: "Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils. Evidence C
Keep apart or take care
- caution With Alliums (onion family): Onions, garlic and leeks are said to stunt beans and peas (allium root exudates may reduce nodulation). Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
- caution With Alliums (onion family): Beans and peas are traditionally kept away from onions, garlic and leeks. Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
- caution With Fennel: Fennel is reported to suppress beans and peas growing next to it. Evidence C
Shared pests and diseases
- Root rots: Fusarium and Aphanomyces root rots build up where legumes repeat. Evidence C
Questions about Yardlong bean
- How far apart should I plant Yardlong bean?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–50 cm (12–20 in).
- Does Yardlong bean need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Yardlong bean need?
- Moderate water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Yardlong bean?
- It tolerates about 5 °C (41 °F) once established, roughly USDA zone 11. As an annual it is usually planted out after the last frost.
- When does Yardlong bean flower?
- About 6–8 weeks after planting, for 9–13 weeks.
- Is Yardlong bean poisonous to cats and dogs?
- For cats it is not well documented; for dogs not well documented; for people mildly toxic. Raw beans contain lectins and trypsin inhibitors that upset the stomach; cook before eating.
- What grows well with Yardlong bean?
- "Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils.
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- EcoCrop crop environmental requirements, FAO
- Flora & Fauna Web, National Parks Board, Singapore
- University extension gardening guides (general), Various land-grant university extensions
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Pods are picked at 30 to 60 cm, before the seeds swell.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Bush bean Phaseolus vulgaris
- Garden pea Pisum sativum
- Sweet pea Lathyrus odoratus
- Runner bean Phaseolus coccineus
- Broad bean (fava) Vicia faba
- Lima bean Phaseolus lunatus
- Cowpea (black-eyed pea) Vigna unguiculata
- Soybean (edamame) Glycine max