Citrus
Eureka Lemon
Citrus limon 'Eureka' · Rutaceae
Also called: True Lemon, Four Seasons Lemon
Eureka Lemon (Citrus limon 'Eureka') is a moderate-water citrus well suited to Tucson and the low desert. It thrives in full sun, with a moderate to fast growth rate. Expect white, fragrant blooms Main bloom late winter to spring.
Eureka Lemon at a glance
- Water use
- Moderate (established)
- Sun
- Full sun (8+ hours). In Tucson, provide afternoon shade or trunk protection (white latex paint/trunk wrap) for young trees to prevent sunburn.
- Mature size
- 12-20 ft tall and wide; commonly kept smaller with pruning. Often grafted on dwarfing rootstock for 8-12 ft.
- Growth rate
- Moderate to fast
- Bloom
- White, fragrant, Main bloom late winter to spring (Feb-Apr); ever-bearing tendency with sporadic bloom year-round in Tucson.
- Cold hardiness
- USDA 9a-9b. Frost-sensitive; lemons are among the most cold-tender citrus. Damage begins around 28-30°F. Protect young trees below ~32°F.
- Soil
- Well-drained soil; tolerates Tucson's alkaline, low-organic native soil but performs best with improved drainage. Avoid planting in caliche without breaking through it; do not amend the backfill heavily.
- Native range
- Cultivar; lemons originate from Asia (hybrid of citron and sour orange). 'Eureka' selected in California in the 1850s.
- Best used as
- Edible fruit (culinary, juice, zest), Backyard/landscape fruit tree, Container specimen
- Wildlife
- Fragrant blossoms attract bees and other pollinators.
- Toxicity
- Fruit edible and non-toxic to people. Foliage/peel essential oils (limonene, psoralens) can cause mild GI upset in dogs/cats; thorns can injure. Generally low concern.
How to grow Eureka Lemon in Tucson & the low desert
Watering
Deep, infrequent irrigation: every 7-10 days in summer, every 3-4 weeks in winter. Water to 3 ft deep out to the dripline/canopy edge; let the top few inches dry between waterings. Never keep the trunk base wet.
Fertilizer & nutrients
Apply nitrogen 3 times yearly to mature trees: Feb (around Valentine's Day), May (Memorial Day), and Aug-Sep (Labor Day). Roughly split ~1-1.5 lb actual N per year for a mature tree; iron/zinc/manganese chelates correct desert micronutrient deficiencies (yellowing leaves). Avoid late-fall nitrogen.
Pruning & care
Minimal pruning needed. Remove deadwood, suckers below the graft, and crossing branches in spring after frost danger. Keep low skirts to shade and protect the trunk from sunburn. Thorny vigorous variety.
Notes
One of the best lemons for Tucson backyards; nearly thornless to thorny, productive, and ever-bearing. Pick fruit as it ripens (heaviest crop late fall through winter, some year-round). Plant in spring (Mar-Apr) after frost to establish before summer heat. Provide frost protection (frost cloth, holiday lights, cover) for the first few winters and during hard freezes. Self-fruitful; no pollinizer needed.
Sources: University of Arizona Cooperative Extension, 'Low Desert Citrus Varieties' (AZ1001); AMWUA Landscape Plants for the Arizona Desert / Arizona Low Water Use plant guidance; UA Pima County Master Gardeners citrus care guidance