Key Lime (Citrus × aurantiifolia)
If you want a citrus that feels like pure Florida sunshine in a single squeeze, Key Lime is it. This classic, small-fruited lime is famous for its sharp, clean acidity and bright aroma—perfect for fresh juice, marinades, pies, and anything that needs that unmistakable “lime pop.”
Key lime trees stay smaller than many other citrus, with glossy leaves, fragrant white blossoms, and fruit that ripens from deep green toward a greenish-yellow or yellow when mature. The flavor is bold and lively, and the tree itself adds that evergreen, orchard presence that makes a food forest feel established.
In Florida planting zone 9, Key lime is best treated as a “warm-microclimate citrus.” Place it where it gets sun and heat, protection from north wind, and excellent drainage. Cold snaps matter with this lime—so choose the warmest spot you have, and be ready to protect it on freezing nights.
Any reference to medicinal or culinary use of plants or plant parts should in no way be considered an endorsement by The Ocala Food Forest or its staff. Research is crucial in safe and proper consumption or experimentational use of any plant.
Plant Information
| Scientific Name: | Citrus × aurantiifolia (Christm.) Swingle |
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| Family Name: | Rutaceae (Citrus family) |
| Common Name(s): | Key Lime, Mexican Lime, West Indian Lime |
| Size: | Small evergreen tree/shrub, often kept 6–12 ft tall with pruning; can reach ~15–20 ft in ideal warm conditions |
| Plant Type: | Evergreen fruit tree (perennial) |
| Origin/Geographic Distribution: | Tropical Asia lineage; widely grown in warm subtropical and tropical regions |
| Native to: | Asia (species lineage); domesticated citrus selection |
| Planted range in the USA: | Most common in Florida, California, Texas, Arizona, and Hawaii (also grown in protected microclimates elsewhere) |
| Conservation Status: | Not applicable (cultivated citrus) |
| Florida Native / Friendly / Invasive: | Not Florida Native; commonly grown in Florida home landscapes (Florida-Friendly when managed with good water and nutrient practices) |
Cultivation
| Planting: | Plant in spring after danger of frost; give roots time to establish before summer heat. Choose the warmest, sunniest, wind-protected spot you have. |
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| Sun Exposure: | Full sun (best fruiting) to light shade |
| Soil Type: | Well-drained soil is critical; raised beds/mounds help in heavier soils. Avoid low, soggy areas. |
| Soil pH: | Adaptable; generally performs best around slightly acidic to neutral (about 5.5–7.5). Micronutrients matter in higher pH soils. |
| Water Requirements: | Moderate; water deeply during establishment and dry spells. Keep soil evenly moist but never waterlogged. |
| Fertilizer Requirements: |
Moderate; use a citrus fertilizer with micronutrients during active growth. Many citrus programs use formulations in the “citrus fertilizer” range (examples often include blends similar to 6-6-6-2, 8-3-9, or 4-2-12—depending on soil needs).
Reminder: Always follow the directions on the package, and adjust based on local soil/leaf tests when possible.
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| Pruning Requirements: | Prune to maintain height (especially in wind), remove dead/diseased wood, and keep the canopy open for airflow. Many gardeners keep Key lime compact for easier cold protection. |
| Growth Rate: | Medium (about 1–2 ft per year when young under good fertility and irrigation; slower in cool weather or poor sites) |
| Companion Planting: | Best companions are living mulches and insectary plants that reduce weeds, support beneficial insects, and avoid crowding the trunk/root flare. |
Tolerance and Hardiness
| Drought Tolerance: | Moderate once established, but drought stress reduces flowering and fruit size—mulch and deep watering help |
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| Frost Tolerance: | Low; very frost-sensitive. Leaf/green-wood injury can begin around 30–32°F (−1 to 0°C). More severe wood damage is common below 29°F (−2°C). Protect during freezes (frost cloth + heat source if needed) and avoid exposed, windy sites. |
| Heat Tolerance: | Handles Florida heat well with adequate moisture. Sunburn/heat injury risk rises when air temps exceed 95°F (35°C) under strong sun; citrus fruit sunburn has been observed when fruit skin temperatures exceed 115°F (46°C). |
| Wind Tolerance: | Low to moderate; branches can break and leaves tear—use windbreaks and keep the tree compact |
| Salt Tolerance: | Low to moderate; avoid direct salt spray and coastal exposure without protection |
| USDA Plant Hardiness Zones: | Best as a perennial in 10–11; can be grown in warmer microclimates of Zone 9 with freeze protection and smart site placement |
Flower and Fruit Information
| Fruit Type: | Hesperidium (citrus berry) |
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| Harvest Time: | Warm months; timing varies by location. Harvest when fruit is full-sized and peel shifts from deep green toward greenish-yellow/yellow. A ripe lime feels heavy for its size and releases strong aroma when lightly scratched. |
| Fruit Description: | Small, round to oval fruit with thin peel; very juicy with bright acidity (classic “Key lime” flavor) |
| Edible Plant: | Yes (fruit) |
| Edible Parts: | Juice and pulp; zest/peel is used for flavoring (wash well before zesting) |
| Medicinal: | Traditionally used as a vitamin C–rich citrus and for general household uses (not a substitute for medical care) |
| Flower Color: | White |
| Flower Shape: | Small, star-like citrus blossoms (often in clusters) |
| Fragrance: | Strongly fragrant—classic citrus bloom scent |
| Flower Bloom Time: | Peak spring bloom (March–May), with possible repeat blooms after warm rains (months can vary by microclimate) |
| Bloom Duration: | Short-lived blossoms; waves of flowering can occur across the warm season |
| Pollination: Self or Other? | Self-fertile; insects help move pollen, but a single tree can fruit |
Wildlife
| Attracts: | Bees and other beneficial insects during bloom; birds may visit for insects and shelter; fallen/overripe fruit can attract wildlife |
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| Pollinators: | Bees, small native pollinators, and other flower-visiting insects |
| Problematic Pest: | Key lime can be affected by Asian citrus psyllid (HLB vector), citrus leafminer, aphids, mites, scale insects, and mealybugs (pressure varies by site). |
Health and Safety
| Toxic: | Generally considered non-toxic; fruit is commonly consumed |
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| Poisonous Parts of Plant: | None commonly recognized as poisonous; thorns can cause punctures |
| Toxic to Humans: | Not toxic; citrus oils/sap can irritate sensitive skin, and thorns can scratch—wear gloves for heavy pruning |
| Toxic to Animals: | Not typically toxic; chewing large amounts of citrus peel/leaves may cause stomach upset |
| Plant Diseases to be aware of: | Citrus greening (HLB), citrus canker, and root/foot rots in poorly drained sites; prioritize drainage, sanitation, and airflow |
Companion Planting
For Citrus × aurantiifolia (Key Lime), companion plants should support soil health, pollinators, and beneficial insects—without crowding the trunk or creating a humid “rot zone.” Keep the base clear, use a wide mulch ring, and place companions just beyond that ring.
Florida Native: Sunshine Mimosa (Mimosa strigillosa)
Zone Range: 8–11
Benefits: Low living mulch that helps suppress weeds and can contribute nitrogen to the system.
Use: Let it fill sunny edges around the tree—keep a clear, mulched ring right at the trunk.
Florida Native: Frogfruit (Phyla nodiflora)
Zone Range: 7–11
Benefits: Pollinator-friendly groundcover that reduces soil splash and supports beneficial insects.
Use: Use in pathways and around the dripline (not directly against the trunk).
Florida Native: Yaupon Holly (Ilex vomitoria)
Zone Range: 7–10
Benefits: Tough native shrub/tree that can function as a windbreak and habitat for beneficial wildlife.
Use: Plant on the north/northwest side as a living wind buffer for cold snaps.
Florida Friendly: Basil (Ocimum basilicum)
Zone Range: All zones as an annual (best in warm seasons)
Benefits: Flowers attract tiny beneficial wasps and other helpers; easy, productive understory herb.
Use: Plant in clusters near (not under) the canopy; let some plants flower for insectary value.
Florida Friendly: Marigolds (Tagetes spp.)
Zone Range: All zones as annuals
Benefits: Adds color and supports beneficial insects; often used as a “border plant” in mixed beds.
Use: Ring the outer mulch edge or plant in nearby beds—don’t crowd the trunk.
Florida Friendly: Pigeon Pea (Cajanus cajan)
Zone Range: 9–11 (often grown as an annual in cooler zones)
Benefits: Nitrogen-fixer and biomass plant; can be pruned for chop-and-drop mulch.
Use: Plant outside the dripline and prune to keep airflow—use prunings as mulch (not piled against the trunk).
Keep the trunk dry and breathing: no vines, no dense plant crowns, and no mulch touching bark. Group companions by irrigation needs, and prioritize airflow to reduce fungal pressure. In Zone 9, freeze protection is part of the plan—choose a warm wall, canopy cover, or windbreak and be ready to cover the tree on cold nights.
Sources & References
Reference list used for general horticultural guidance and Florida-relevant best practices (not medical advice):
- UF/IFAS EDIS — Key Lime (CH092) — cultivar description, fruit maturity cues, and Florida-focused growing considerations.
- UF/IFAS EDIS — Asian Citrus Psyllid (CG097) — key pest background and why monitoring matters (HLB vector).
- Florida-Friendly Landscaping™ Program — water-wise and sustainable landscape recommendations for Florida yards.
- USDA Plant Hardiness Zone Map — zone reference framework for planting suitability and freeze planning.
- Kew — Plants of the World Online (POWO) — taxonomy notes and accepted-name context for Citrus × aurantiifolia.