Alfalfa (lucerne) Medicago sativa
Alfalfa (lucerne) (Medicago sativa) is an evergreen perennial herb in the Fabaceae family, native to Iran and the Caucasus. It grows 60–90 cm (24–35 in) tall and 40–60 cm (16–24 in) wide, wants full sun and low water, and is hardy to about -30 °C (-22 °F). Space plants about 20 cm (8 in) apart.
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Alfalfa (lucerne) at a glance
| Type | Perennial herb, evergreen |
|---|---|
| Family | Fabaceae |
| Mature height | 60–90 cm (24–35 in) |
| Mature spread | 40–60 cm (16–24 in) |
| Spacing | 20 cm (8 in) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 6.5–7.5 |
| Cold hardiness | About -30 °C (-22 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 38 °C (100 °F) |
| Flowering | about 7–10 weeks after planting, for 9–17 weeks |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Yes: sprouts, young leaves |
| Native to | Iran and the Caucasus |
| Common in gardens of | 🇺🇸 United States, 🇨🇦 Canada, 🇦🇷 Argentina, 🇦🇺 Australia, 🇮🇹 Italy, 🇫🇷 France, 🇪🇸 Spain, 🇷🇺 Russia, 🇨🇳 China, 🇮🇷 Iran |
Is Alfalfa (lucerne) toxic?
- People: mildly toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
- Parts: seeds and sprouts in quantity
Raw seeds and sprouts contain L-canavanine; large amounts are linked to lupus-like flares. Lush green forage can cause bloat in grazing animals.
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 Alfalfa (lucerne)
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
Questions about Alfalfa (lucerne)
- How far apart should I plant Alfalfa (lucerne)?
- About 20 cm (8 in) apart, centre to centre. A mature plant spreads 40–60 cm (16–24 in).
- Does Alfalfa (lucerne) need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Alfalfa (lucerne) need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Alfalfa (lucerne)?
- It tolerates about -30 °C (-22 °F) once established, roughly USDA zone 4.
- When does Alfalfa (lucerne) flower?
- About 7–10 weeks after planting, for 9–17 weeks.
- Is Alfalfa (lucerne) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people mildly toxic. Raw seeds and sprouts contain L-canavanine; large amounts are linked to lupus-like flares. Lush green forage can cause bloat in grazing animals.
- What grows well with Alfalfa (lucerne)?
- "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 A (A: strong evidence).
- EcoCrop crop environmental requirements, FAO
- GRIN-Global Taxonomy, USDA ARS
- FAO Irrigation and Drainage Paper 56 — Crop Evapotranspiration, FAO
Notes and assumptions
- The “queen of forages”: roots reach several metres, so it rides out droughts; cut three to eight times a year for hay.
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