Lime Tree Identification Guide
Identify the citrus lime tree (Citrus aurantiifolia and relatives) by its small thorny evergreen form, aromatic oval leaves with narrowly winged petioles, small white flowers, and small round green fruit.
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Key Identifying Features
The lime tree (Citrus aurantiifolia, key lime, and Citrus latifolia, Persian lime) is a small, bushy evergreen citrus tree or shrub, 2-5 m tall, often densely thorny. Identify it by its small, aromatic, oval leaves with narrowly winged petioles, small white five-petaled flowers, and small round-to-oval green fruit. Crushed leaves and scratched peel release a strong lime-citrus oil scent from translucent glands. (Note: this is the citrus lime, not the European linden 'lime tree.')
Leaves & Stems
- Leaves are simple, alternate, oval to elliptical, 4-8 cm (key lime smaller), glossy green, with finely scalloped margins.
- The petiole is narrowly winged (small flange), and leaves are dotted with oil glands — held to light they show translucent dots and smell strongly of lime.
- Twigs are green and armed with sharp, slender spines, especially key lime.
- New growth may be pale green to slightly bronze.
Flowers & Fruit
- Flowers are small, white, five-petaled, about 1.5-2.5 cm, fragrant, borne singly or in small clusters; key lime buds are often white (not purple-tinged like lemon).
- Fruit is a small round-to-oval green hesperidium, 3-6 cm, ripening to pale yellow if left on the tree.
- Inside is pale green, segmented pulp; key limes are small and seedy, Persian limes larger and seedless.
How to Tell It Apart from Look-Alikes
- Lemon (Citrus limon): Larger elliptical yellow fruit with a nipple, purple-tinged new growth and flower buds, and stiffer thorns.
- Orange (Citrus sinensis): Larger round orange fruit, larger leaves.
- Kaffir/makrut lime (Citrus hystrix): Has distinctive double (hourglass) leaves with a winged blade as large as the leaf itself, and knobbly fruit.
- Calamondin: Small orange fruit, not green.
The small thorny evergreen habit + small aromatic winged-petiole leaves + white flowers + small round green fruit identifies a lime.
Where You'll Find It
Limes grow in tropical and subtropical climates (USDA zones 9-11) — home gardens, orchards, and patio containers in cooler areas. They need full sun, warmth, and well-drained soil, and are very frost-sensitive. Look for the compact thorny bush hung with small green fruit.
Quick ID Checklist
- Small bushy, thorny evergreen citrus
- Small oval glossy leaves with narrowly winged petioles
- Translucent oil dots and strong lime scent when crushed
- Small white five-petaled fragrant flowers
- Small round-to-oval green fruit, segmented pulp
- Frost-sensitive, grown in warm climates
Frequently asked questions
How do I tell a lime tree from a lemon tree?
Lime trees are smaller and bushier with small green round fruit and white flower buds, while lemon trees have larger elliptical yellow fruit with a nipple and purple-tinged new growth and flower buds. Crushing the leaves, both smell citrusy but distinctly lime versus lemon.
Is the citrus lime tree the same as the linden 'lime tree'?
No. In Europe 'lime tree' often means linden (Tilia), a large deciduous shade tree. This guide covers the citrus lime, a small thorny evergreen that produces small green fruit.
Why do limes turn yellow sometimes?
Limes are usually picked green, but if left on the tree they ripen to a pale yellow. A yellowing lime is simply mature; it is still a lime, not a lemon, distinguishable by its rounder shape and lime aroma.
What is a makrut (kaffir) lime and how is it different?
Makrut lime (Citrus hystrix) has distinctive double, hourglass-shaped leaves with a winged section as large as the blade, and knobbly bumpy fruit. Common limes have single oval leaves and smooth-skinned round fruit.