alfalfa
Medicago sativa · Fabaceae
alfalfa (Medicago sativa) is a perennial herbaceous plant in the Fabaceae family. It is introduced to North America rather than native. USDA records it as hardy in zone 2 and warmer, down to about -43°F.
⚠ Allelopathic. USDA flags this plant as releasing compounds that can suppress the growth of plants near it. Give neighbours extra room, and expect some companions to struggle regardless of how well their conditions match.
Both flags are quoted from USDA PLANTS, not inferred.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | introduced USDA |
| Mature height | 2 ft USDA |
| Light | full-sun USDA |
| Water need | medium USDA |
| Growth rate | rapid USDA |
| Soil pH | 6.2–8.5 USDA |
| Bloom | March–May USDA |
| Flower color | Purple USDA |
| Hardiness zones | 2 and warmer USDA |
| Guild layer | nutrient Derived |
| Nursery availability | Routinely Available USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It needs full sun. USDA rates it as having moderate water needs. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 6.2 to 8.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 2.
Size and growth
At maturity it reaches about 2 ft, making it about knee height. It grows quickly.
Bloom period
USDA records a bloom period of March through May. Flowers are purple.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is green, fine in texture. Its flowers are conspicuous. It carries conspicuous autumn colour. Its active growth period is spring, summer, fall. USDA rates its lifespan as long.
What the site needs to provide
USDA records it across sites receiving 16 to 65 inches of annual precipitation. It needs at least 90 frost-free days to finish its season. It roots to at least 24 inches. Fertility requirement: medium.
Propagating it
Seed is the only propagation method USDA lists. Division and cuttings are not listed as options. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It spreads vegetatively at a slow rate.
Resilience and wildlife
Browsing animals find it highly palatable, so expect deer and rabbits to take an interest. Its fire tolerance is rated high. Its growth form is recorded as single crown.
Role in a guild
Nutrient layer. In a layered planting this is it contributes to soil fertility rather than to structure. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Medicago
- black medick Medicago lupulina
- burclover Medicago polymorpha
- snail medick Medicago scutellata
Similar role and hardiness
- chickpea milkvetch Astragalus cicer
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol MESA, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Allelopathy, Bloom, Bloom end, browse palatability, cold stratification, Drought tolerance, Edible, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, Type, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer.
Read our full data sources and methodology.
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