Garden lupin Lupinus polyphyllus
Garden lupin (Lupinus polyphyllus) is a deciduous perennial flowering plant in the Fabaceae family, native to Western North America (Alaska to California). It grows 80 cm–1.4 m (31 in–4.6 ft) tall and 50–90 cm (20–35 in) wide, wants full sun and moderate water, and is hardy to about -34 °C (-29 °F). Space plants about 60 cm (24 in) apart.
Plan Garden lupin in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Garden lupin at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Fabaceae |
| Mature height | 80 cm–1.4 m (31 in–4.6 ft) |
| Mature spread | 50–90 cm (20–35 in) |
| Spacing | 60 cm (24 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Soil pH | 5.5–7 |
| Cold hardiness | About -34 °C (-29 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 26 °C (79 °F) |
| Flowering | from about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Western North America (Alaska to California) |
| Common in gardens of | 🇬🇧 United Kingdom, 🇳🇴 Norway, 🇩🇪 Germany, 🇸🇪 Sweden |
| Invasive in | Norway (Black List), New Zealand (riverbeds), Iceland, Finland, Germany (locally): check local rules before planting |
Is Garden lupin toxic?
- People: moderately toxic
- Cats: moderately toxic
- Dogs: moderately toxic
- Parts: seeds, pods, all parts
Quinolizidine alkaloids (lupanine, sparteine) cause vomiting, drooling and nervous-system signs; the seeds are most toxic.
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 Garden lupin
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
See Garden lupin in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Monet’s gardens at Giverny (70 plants)
- Riverside botanical garden (15 plants)
Questions about Garden lupin
- How far apart should I plant Garden lupin?
- About 60 cm (24 in) apart, centre to centre. A mature plant spreads 50–90 cm (20–35 in).
- Does Garden lupin need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Garden lupin need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Garden lupin?
- It tolerates about -34 °C (-29 °F) once established, roughly USDA zone 4.
- When does Garden lupin flower?
- From about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Garden lupin poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs moderately toxic; for people moderately toxic. Quinolizidine alkaloids (lupanine, sparteine) cause vomiting, drooling and nervous-system signs; the seeds are most toxic.
- What grows well with Garden lupin?
- "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 B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
- CABI Invasive Species Compendium, CABI
- USDA PLANTS Database, USDA NRCS
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Short-lived (3 to 5 years); fixes nitrogen with root nodules; seeds readily and can escape into verges and river gravels.
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