Key lime Citrus x aurantiifolia
Key lime (Citrus x aurantiifolia) is an evergreen perennial fruit plant in the Rutaceae family, native to Northeast India and Southeast Asia (hybrid of Citrus micrantha and citron). It grows 2–4 m (6.6–13 ft) tall and 2–4 m (6.6–13 ft) wide, wants full sun and moderate water, and is hardy to about 0 °C (32 °F). Space plants about 3.5 m (11 ft) apart.
Plan Key lime in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Key lime at a glance
| Type | Perennial fruit plant, evergreen |
|---|---|
| Family | Rutaceae |
| Mature height | 2–4 m (6.6–13 ft) |
| Mature spread | 2–4 m (6.6–13 ft) |
| Spacing | 3.5 m (11 ft) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 6–7.5 |
| Cold hardiness | About 0 °C (32 °F) once established (roughly USDA zone 10) |
| Heat stress | Likely above about 38 °C (100 °F) |
| Flowering | from about March for 9–34 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Yes: fruit, zest, leaves |
| Native to | Northeast India and Southeast Asia (hybrid of Citrus micrantha and citron) |
| Common in gardens of | 🇲🇽 Mexico, 🇹🇭 Thailand, 🇺🇸 United States |
Is Key lime toxic?
- People: mildly toxic
- Cats: moderately toxic
- Dogs: mildly toxic
- Parts: leaves, peel, sap
Furanocoumarins in the sap and peel cause skin photosensitivity in people, and citrus oils cause vomiting and drooling in pets.
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 Key lime
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
Keep apart or take care
- caution With Sweet orange: Asian citrus psyllid spreads huanglongbing (citrus greening) between citrus and relatives such as orange jasmine (Murraya). Keep new citrus away from infected or neglected hosts. Evidence B
Shared pests and diseases
- Citrus greening (HLB): Spread by the Asian citrus psyllid, which also breeds on curry leaf (Murraya). Evidence B
- Xylella fastidiosa: Insect-spread bacterium (EU quarantine pest) hitting olive, lavender, rosemary, oleander, Prunus and citrus. Evidence B
Questions about Key lime
- How far apart should I plant Key lime?
- About 3.5 m (11 ft) apart, centre to centre. A mature plant spreads 2–4 m (6.6–13 ft).
- Does Key lime need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Key lime need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Key lime?
- It tolerates about 0 °C (32 °F) once established, roughly USDA zone 10.
- When does Key lime flower?
- From about March for 9–34 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Key lime poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs mildly toxic; for people mildly toxic. Furanocoumarins in the sap and peel cause skin photosensitivity in people, and citrus oils cause vomiting and drooling in pets.
- What grows well with Key lime?
- There is no well-documented companion pairing for Key lime. Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- UF/IFAS Extension tropical and subtropical fruit and landscape publications, University of Florida
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
- University extension gardening guides (general), Various land-grant university extensions
Notes and assumptions
- The most cold-sensitive common citrus (zones 10–11); thorny, small seeded fruit. Grown in a container and brought indoors in cooler climates.
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
- Lemon tree (dwarf) Citrus limon
- Curry tree Murraya koenigii
- Kaffir lime Citrus hystrix
- Common rue Ruta graveolens
- Sweet orange Citrus x sinensis
- Mandarin orange Citrus reticulata
- Persian lime Citrus x latifolia
- Grapefruit Citrus x paradisi