Winged bean Psophocarpus tetragonolobus
Winged bean (Psophocarpus tetragonolobus) is an annual vegetable in the Fabaceae family, native to Tropical Asia (probably New Guinea or Southeast Asia). It grows 2–4 m (6.6–13 ft) tall and 40–80 cm (16–31 in) wide, wants full sun and moderate water, and is hardy to about 8 °C (46 °F). Space plants about 30 cm (12 in) apart.
Plan Winged bean in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Winged bean at a glance
| Type | Annual vegetable |
|---|---|
| Family | Fabaceae |
| Mature height | 2–4 m (6.6–13 ft) |
| Mature spread | 40–80 cm (16–31 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance moderate |
| Soil pH | 5.5–7 |
| Cold hardiness | About 8 °C (46 °F) once established (roughly USDA zone 11) |
| Heat stress | Likely above about 35 °C (95 °F) |
| Flowering | about 7–10 weeks after planting, for 13–21 weeks |
| Days to maturity | About 120 days from planting |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Yes: young pods, leaves, flowers, tuberous roots (cooked), mature seeds (cooked) |
| Native to | Tropical Asia (probably New Guinea or Southeast Asia) |
| Common in gardens of | 🇹🇭 Thailand, 🇸🇬 Singapore |
Is Winged bean toxic?
- People: mildly toxic
- Cats: not well documented
- Dogs: not well documented
- Parts: raw seeds
Raw seeds contain trypsin inhibitors and lectins 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 Winged 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 Winged bean
- How far apart should I plant Winged bean?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 40–80 cm (16–31 in).
- Does Winged bean need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Winged bean need?
- Moderate water. Drought tolerance is low and waterlogging tolerance moderate.
- How cold-hardy is Winged bean?
- It tolerates about 8 °C (46 °F) once established, roughly USDA zone 11. As an annual it is usually planted out after the last frost.
- When does Winged bean flower?
- About 7–10 weeks after planting, for 13–21 weeks.
- Is Winged bean poisonous to cats and dogs?
- For cats it is not well documented; for dogs not well documented; for people mildly toxic. Raw seeds contain trypsin inhibitors and lectins that upset the stomach; cook before eating.
- What grows well with Winged 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
- Plants For A Future database, PFAF
- Flora & Fauna Web, National Parks Board, Singapore
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- A tender perennial grown as an annual; most cultivars flower only under short days.
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
- Yardlong bean Vigna unguiculata subsp. sesquipedalis