Tree · Rutaceae
Lime
Citrus × latifolia
Give it full sun, sharp drainage, and steady warmth, and a lime tree fruits for years.
Full sun
Every 5–10 days
USDA 9–11
8–20 ft · 2.4–6.1 m
Overview
The Persian lime is the seedless, smooth-skinned lime you find at almost every market, a hybrid citrus grown for its sharp, aromatic juice. It makes a handsome small tree, reaching 8 to 20 feet (2.5 to 6 m) with a rounded canopy, and carries fruit on and off through much of the year in warm climates. Most growers pick the limes while still green, when the acid is at its peak.
This is a warm-climate tree at heart, happy in the ground across USDA zones 9 to 11 and grown in a pot anywhere colder so it can shelter from frost. It takes the cold a little better than the Mexican (Key) lime, but a hard freeze still does real damage. Full sun, free-draining soil, and protection from biting wind are what it asks for.
Limes are not fussy day to day, yet a few things decide success. Wet feet bring root and foot rot, the wrong soil pH locks out nutrients, and a short list of citrus diseases can undo a tree if you miss the early signs. Get the drainage and feeding right and you have a long-lived tree that pays back the care.
Care
The short version: full sun, free-draining sandy loam, and deep but infrequent watering once the top few centimeters dry, fed through the growing season with a citrus fertilizer that carries the trace nutrients limes need.
Light
A lime tree wants full sun, ideally 8 hours or more a day, to crop well. 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 out, 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 the soil pH drifting too high is what brings on the yellow, veiny leaves of 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, so a cold snap calls for cover or a move indoors for potted trees.
Humidity
Average humidity of 40% to 60% suits a lime fine, so there's 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 heads off the yellowing before it starts.
Pruning
Limes need little pruning. Take out dead, damaged, or crossing branches and any suckers growing below the graft union, and thin lightly after harvest to open the canopy. Wear gloves, because the peel and juice oils plus sun can blister bare 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's time.
Size & spacing
A mature lime reaches 8 to 20 feet (2.5 to 6 m) tall and about as wide, 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, and the main crop runs from summer into winter, with the fruit picked 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
Most lime trouble starts on the leaves, so it pays to look them over often. Some problems are a quick fix with sanitation or feeding, while two of the diseases below are serious enough to report. Match what you see, then act before it spreads to the rest of the tree.
Corky tan scabs ringed by yellow on leaves, twigs, and fruit
This is citrus canker, a bacterium carried on wind-driven rain and dirty pruning tools. The raised, corky lesions wear a yellow halo and show up on the fruit rind as well as the leaves, which sets it apart from greasy spot. Bag the infected growth, disinfect tools between cuts, and where canker is under quarantine, report it to your local agricultural authorities.
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
Lopsided yellow blotches, twig dieback, and small bitter fruit
This is citrus greening, or huanglongbing, the disease that has gutted citrus across whole regions. The Asian citrus psyllid spreads it, and the giveaway is a blotchy mottle that runs straight across the leaf midrib instead of mirroring side to side, paired with lopsided fruit. There is no cure, so remove and destroy infected trees, control the psyllid, and report any 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 underneath the leaves
This is greasy spot, a fungus that takes hold in warm, humid weather and feeds on the leaves that drop and rot under the tree. The worst leaf fall comes in late summer and fall. Rake up and destroy the fallen litter, open the canopy for airflow, 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
Yellow leaves with green veins on the newest growth
Yellowing that leaves the veins green and hits the youngest leaves first points to a micronutrient shortage of iron, manganese, or zinc, usually because the soil pH is too high or the roots sit wet. Older leaves yellowing all over is a nitrogen story instead. Spray a chelated micronutrient feed, switch to a citrus fertilizer that carries those trace elements, and fix the drainage.
Fix:
- Apply a chelated micronutrient foliar spray
- Switch to a citrus fertilizer that includes micronutrients
- Correct drainage and avoid overwatering
Toxicity
The juice and flesh are safe to eat, but the rest of the tree is a different story. The peel, leaves, and 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
Chewing the peel, leaves, or seeds tends to bring on vomiting, loose stools, and a dull, low mood. The mouth or skin may also be irritated by the oils.
Dogs Mild
A dog that gnaws on peel, leaves, or seeds usually gets an upset stomach and a bout of diarrhea, sometimes looking flat and depressed afterward.
Horses Mild
The same peel and leaf oils that bother pets can leave a horse off its feed and queasy, so keep prunings and dropped fruit out of the paddock.
Rabbits Caution
The aromatic oils in peel and foliage don't suit a rabbit's sensitive gut, and there's little reason to risk it. Skip the lime altogether.
Livestock Caution
Goats and other stock may nibble fallen fruit without trouble, but a belly full of bitter peel and leaves can sour the stomach. Fence them off from prunings and windfalls to be safe.
Birds Caution
A taste of the flesh is generally tolerated, yet the strong oils in peel and leaves can irritate a small bird. Offer only a little clean fruit and keep the rind away.
People Fruit safe
The juice and flesh are a kitchen staple and safe to eat. The real catch is the skin: peel oils and juice in sunlight can 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 the labels actually mean.
Bearss
This is the standard Persian lime grown across the US and especially Florida, a nearly thornless, seedless tree whose smooth-skinned fruit ripens from green to yellow.
Tahiti
Tahiti is just 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
Limes are multiplied by the nursery method of grafting or by slower home techniques, though only grafting gives you the full benefit of a rootstock.
GraftingDemanding
Spring to early summer when the bark slips · 1 to 3 years to bearing
Grafting is how nurseries do it, and for good reason. Bud or graft your lime onto a disease-resistant, often dwarfing rootstock in spring or early summer while the bark still slips, and the young tree gains vigor, cold tolerance, and disease resistance before it starts bearing in 1 to 3 years.
Air layeringModerate
Warm growing season · Several months to root, then 1 to 2 years to establish
Air-layering works at home during the warm growing season, taking several months to root and then 1 to 2 years to settle in. The catch is that an own-rooted tree skips the rootstock, so it ends up 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 taken in late spring or summer will root and reach a usable size in about 1 to 2 years. Like air-layered trees, these own-root plants miss out on the cold hardiness and disease protection a rootstock would give them.
Myths
Limes are just unripe lemons.
Limes and lemons are separate citrus, and Persian lime is its own hybrid, Citrus x latifolia. Growers pick limes green for their sharp acidity, but the fruit turns yellow when fully ripe, which is nothing like an unripe lemon.
You can grow a true Persian lime tree from a seed in the fruit.
Persian lime 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 part of a citrus plant is dangerously poisonous to dogs and cats.
The fruit 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.