Citrus
Mexican (Key) Lime
Citrus × aurantiifolia · Rutaceae
Also called: Key Lime, West Indian Lime, Bartender's Lime, Mexican Lime
Mexican (Key) Lime (Citrus × aurantiifolia) is a moderate-water citrus well suited to Tucson and the low desert. It thrives in full sun, with a moderate growth rate.
Mexican (Key) Lime at a glance
- Water use
- Moderate (established)
- Sun
- Full sun (8+ hours). Young trees benefit from afternoon shade and trunk painting to prevent sunburn in Tucson's intense sun.
- Mature size
- 6-12 ft tall and wide; shrubby small tree, easily kept compact or grown in a container.
- Growth rate
- Moderate
- Bloom
- White (sometimes purple-tinged buds), fragrant, Spring main bloom with sporadic ever-bearing flowering through the warm season.
- Cold hardiness
- USDA 9b (borderline in 9a). Most cold-sensitive of common limes; injured at ~30-32°F. Needs reliable frost protection in Tucson and is best in a warm microclimate or large pot that can be moved.
- Soil
- Well-drained; tolerant of alkaline desert soil but intolerant of standing water and wet feet.
- Native range
- Cultivar/species of Southeast Asian / Indo-Malayan origin; naturalized in Mexico and the Caribbean.
- Best used as
- Edible fruit (juice, cooking, key lime pie, cocktails), Container/patio tree, Backyard fruit tree in warm microclimates
- Wildlife
- Blossoms attract bees and pollinators.
- Toxicity
- Fruit edible/non-toxic to people; high-furanocoumarin peel oil causes phytophotodermatitis (skin + sun = burns/blistering) in people, and mild toxicity to dogs/cats. Very thorny.
How to grow Mexican (Key) Lime in Tucson & the low desert
Watering
Deep soak every 7-10 days in summer heat, stretching to every 3-4 weeks in winter; wet the soil to ~3 ft deep across the canopy footprint and keep the trunk dry.
Fertilizer & nutrients
Nitrogen 3x/year (Feb, May, Aug/Sep). Use citrus food and supplement iron/zinc/manganese chelates to correct alkaline-soil micronutrient deficiencies; avoid nitrogen after early fall.
Pruning & care
Light pruning only. This is a small, twiggy, very thorny tree; remove deadwood, suckers, and crossing limbs in spring. Keep a low canopy to shade the trunk.
Notes
Small fragrant fruit harvested mainly summer into fall; pick green to yellowing. The classic margarita/key-lime lime. Best grown in a warm spot against a south/west wall or in a movable container due to high frost sensitivity. Plant in spring after frost. Self-fruitful. Cover or bring in during freezes.
Sources: University of Arizona Cooperative Extension, 'Low Desert Citrus Varieties' (AZ1001); Arizona-Sonora Desert Museum / UA Master Gardeners citrus guidance; UC Riverside Citrus Variety Collection