Tree · Rutaceae
Lime
Citrus × latifolia
Under full sun, with sharp drainage and lasting warmth, a lime tree sets glossy fruit for years.
Full sun
Every 5–10 days
USDA 9–11
8–20 ft · 2.4–6.1 m
Overview
The Persian lime hangs smooth, oval fruit of a deep, waxy green among glossy leaves, the seedless, thin-skinned lime found at almost every market and grown for its sharp, aromatic juice. It builds a handsome small tree of 8 to 20 feet (2.5 to 6 m) with a dense, rounded canopy, and it carries that fruit on and off through much of the year in warm climates. Growers pick the limes while the skin is still green, when the flesh inside runs most acidic.
This is a warm-climate tree, at home in the ground across USDA zones 9 to 11 and set in a pot anywhere colder so it can be pulled clear of frost. Its wood stands the cold a little better than the Mexican (Key) lime, yet a hard freeze still scorches the leaves and damages the branches. Full sun, free-draining soil, and shelter from biting wind are what it wants.
Up close the lime rewards a careful eye, since the earliest troubles read on the leaves and fruit themselves. Wet feet rot the roots and lower trunk, an off soil pH drains the green from the foliage, and a short list of citrus diseases can undo a tree if the first marks go unread. Keep the drainage and feeding right and the tree stays deep-leafed and long-lived, heavy with green fruit.
Care
The short version: full sun; a loose, free-draining sandy loam; a deep soak only now and then once the top centimeters dry; and a growing-season citrus feed that supplies the trace nutrients a lime craves.
Light
A lime tree wants full sun, ideally 8 hours or more a day, to set a heavy crop and hold its leaves a deep green. It will tolerate a little partial sun, but shade thins the canopy and cuts the harvest.
Water
Water deeply when the top few centimeters of soil dry, then let it drain fully. Established in-ground trees get by on less, while pots dry fast and may need water every few days in heat. The one thing to avoid is waterlogged roots, which invite foot and root rot.
Soil
Plant in well-drained sandy loam, since standing water is the fastest way to lose a citrus tree. A pH of 6.0 to 7.5 keeps the nutrients available, and a pH that drifts too high is what drains the green from the leaves into a yellow, veiny micronutrient deficiency.
Temperature
Limes thrive in warmth, roughly 32°F to 95°F (0°C to 35°C), and grow year-round where it stays mild. They are tender to frost, and a cold snap will brown the leaves, so cover the tree or move a potted one indoors.
Humidity
Average humidity of 40% to 60% suits a lime fine, so there is no special target to hit. Good airflow through the canopy matters more, since warm, still, humid air is what greasy spot and other fungal diseases feed on.
Feeding
Feed through the active growing season, from spring into late summer, with a balanced citrus fertilizer that includes magnesium, manganese, zinc, and iron. Those micronutrients are exactly what limes run short on, and a complete citrus feed keeps the foliage green before the yellowing starts.
Pruning
The lime demands only light pruning. Snip out limbs that have died, taken damage, or cross one another, along with suckers pushing up from under the graft union, then thin gently once the fruit is picked to open the leafy canopy. Wear gloves, since the fragrant oils in the peel and juice, struck by sun, can blister exposed skin.
Repotting
Move a container tree into a larger pot every 2 to 3 years in spring. Roots circling the pot or escaping the drainage holes, water that runs straight through, and slowed growth with yellowing leaves all say it is time.
Size & spacing
A mature lime reaches 8 to 20 feet (2.5 to 6 m) tall and about as wide, a broad dome of dark, glossy foliage, so give it real room to spread. In a pot it stays smaller, but it still wants air moving freely around the whole canopy.
When to plant
A lime tree wants warmth and no frost, so set it out in spring once the soil and air have settled into reliable heat. In warm climates it blooms on and off all year, small white flowers giving way to fruit, and the main crop runs from summer into winter, with the limes picked while still green for the sharpest juice.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant in spring after all danger of frost, once soil and air are reliably warm.
- Harvest: Blooms on and off year-round in warm climates; main harvest summer into winter, with fruit picked while green for highest acidity.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
The first signs of trouble on a lime write themselves on the leaves and fruit, in mottling, scabs, and yellowing, so a close look pays off. Some marks clear with sanitation or feeding, while two of the diseases below are serious enough to report. Read what the surface shows, then act before it spreads to the rest of the tree.
Rough tan corky scabs ringed in yellow across leaves, twigs, and peel
Citrus canker stamps raised, corky tan scabs onto the leaves, twigs, and fruit rind, each one water-soaked at the margin and circled by a bright yellow halo. That the scabs pit the rind as well as the foliage is what tells canker from greasy spot. The bacterium travels on wind-driven rain and dirty pruning tools, so bag the infected growth, disinfect tools between cuts, and report it to agricultural authorities where canker is under quarantine.
Fix:
- Remove and bag infected leaves and twigs
- Disinfect pruning tools between cuts
- Apply preventive copper sprays
- Report to local agricultural authorities in regulated/quarantine areas
Skewed yellow blotching, twigs dying back, and small, deformed fruit
Citrus greening, or huanglongbing, paints a blotchy, uneven yellow mottle that spills across the leaf midrib rather than mirroring side to side, and it twists the new growth and kills back the twigs. The fruit comes small, lopsided, and bitter with aborted seeds. The Asian citrus psyllid spreads it and there is no cure, so remove and destroy the infected tree, control the psyllid, and report the find to agricultural authorities.
Fix:
- There is no cure; remove and destroy infected trees to protect others
- Control Asian citrus psyllid with approved insecticides or oils
- Report finds to agricultural authorities
Yellow blotches above and greasy brown blisters beneath the leaves
Turn a leaf over and greasy spot shows its hand: yellow mottling on the upper surface answered by raised, greasy, blister-like brown lesions on the underside. This fungus takes hold in warm, humid weather and lives on the leaves that drop and rot beneath the tree, with the heaviest fall in late summer. Rake and destroy the fallen litter, open the canopy, and time a copper or oil spray for early summer.
Fix:
- Rake up and destroy fallen leaves to cut inoculum
- Apply a copper fungicide or horticultural oil in early to mid summer per label
- Prune to improve air circulation
Yellowed blades with green veins, the newest leaves hit first
When the leaf blade fades to yellow but the veins hold a crisp green network, worst on the youngest leaves, the tree is short on iron, manganese, or zinc. High soil pH or wet roots usually locks those micronutrients out. A flat, uniform yellowing of the older leaves is a different, nitrogen story. Spray a chelated micronutrient feed, move to a citrus fertilizer that carries those trace elements, and correct the drainage.
Fix:
- Apply a chelated micronutrient foliar spray
- Switch to a citrus fertilizer that includes micronutrients
- Correct drainage and avoid overwatering
Toxicity
The pale green flesh and its sharp juice are safe to eat, but the rest of the tree is a different story. The glossy peel, the leaves, and the few seeds carry essential oils and psoralens that upset a pet's stomach and can blister human skin in sunlight. Keep prunings, peels, and seeds away from animals, and wear gloves when you handle the tree.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
The oils packed into the glossy peel, leaves, and seeds turn a chewing cat sick, bringing vomiting, loose stools, and a dull, low mood, and they can leave the mouth or skin sore.
Dogs Mild
A dog that gnaws the bitter peel, leaves, or seeds ends up with an upset stomach and diarrhea, often looking flat and depressed while the same oils work through it.
Horses Mild
The pungent oils in peel and leaf leave a horse off its feed and queasy, so keep the trimmings and any dropped, green-skinned fruit swept out of the paddock.
Rabbits Caution
The sharp aromatic oils soaked into peel and foliage are too much for a rabbit's delicate gut, and with nothing to gain, lime is best kept away from rabbits altogether.
Livestock Caution
Goats and other stock may lip a fallen fruit without harm, but a mouthful of bitter peel and leaf sours the stomach, so fence them off from prunings and windfalls to be safe.
Birds Caution
A small bird usually manages a taste of the pale green flesh, yet the strong oils in the peel and leaves can irritate, so offer only a little clean fruit and keep the rind away.
People Fruit safe
The juicy, pale green flesh and its sharp juice are a kitchen staple and safe to eat. The oily skin is the catch, since its oils and juice in sunlight raise a blistering 'margarita burn,' so rinse your hands after handling.
Wear gloves when pruning or zesting; lime juice or peel oils on skin exposed to sunlight can trigger phytophotodermatitis ('margarita burn'), a painful blistering rash.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Persian lime goes by more than one name, and a couple of forms turn up at nurseries. Here is what those labels actually mean.
Bearss
Bearss is the standard Persian lime of the US and especially Florida, a nearly thornless, seedless tree whose smooth-skinned fruit ripens from deep green to a pale yellow.
Tahiti
Tahiti is another name for the same triploid seedless lime as Bearss, a vigorous tree that takes the cold better than the Mexican (Key) lime.
Companions
A lime grows best beside flowers that pull in the predators of its pests, and worst with grass crowding the trunk where rot likes to start.
Plant near
Sweet alyssum: Its tiny flowers attract hoverflies and parasitic wasps that help control aphids and psyllids.
Marigold: Draws beneficial insects and may deter some pests around young trees.
Keep apart
Turf grass grown up to the trunk: Lawn competes for water and nutrients and holds moisture against the trunk, raising foot-rot risk; keep a mulched, grass-free zone.
How to propagate
A lime can be increased two ways: by the graft that nurseries use, or by slower techniques done at home, though only a graft brings the full gifts of a rootstock.
GraftingDemanding
Spring to early summer when the bark slips · 1 to 3 years to bearing
Grafting is the nursery method, worked in spring or early summer while the bark peels back cleanly and slips from the wood. Bud or graft the lime onto a disease-resistant, often dwarfing rootstock then, and the young tree draws vigor, cold tolerance, and disease resistance from below before it bears in 1 to 3 years.
Air layeringModerate
Warm growing season · Several months to root, then 1 to 2 years to establish
Air-layering is a home method for the warm growing season, wrapping a girdled stem until roots feather out over several months, then 1 to 2 years to establish. The trade-off is that this own-rooted tree has no rootstock beneath it, leaving it more cold-tender and more prone to disease.
Stem cuttingsModerate
Semi-hardwood cuttings in late spring or summer · 1 to 2 years
Semi-hardwood cuttings, the firm but still-green stems of late spring or summer, root and grow to a usable size in about 1 to 2 years. As with air-layered trees, these own-root plants have none of the cold hardiness or disease protection a rootstock would give.
Myths
Limes are just unripe lemons.
A lime and a lemon are different fruits, and the Persian lime stands as its own hybrid, Citrus x latifolia. On the branch a lime hangs deep green and glossy at its sharp-acid peak, then colors to a clear yellow once fully ripe, and that yellow marks ripeness, not the skin of a green, immature lemon.
The seeds nestled inside a lime will sprout into a matching Persian lime tree.
Slice a Persian lime open and you find the pale flesh nearly empty, because it is a seedless triploid that almost never sets a viable seed, so nurseries graft it instead. Any stray seedling you did manage to sprout would not come true to the parent tree.
Every piece of the citrus tree is gravely poisonous to any dog or cat.
The juicy green flesh causes no more than a mild stomach upset. It is the essential oils and psoralens packed into the peel, leaves, and seeds that the ASPCA flags as toxic, not the juicy part people eat.