Tree · Lauraceae
Avocado
Persea americana
Give it full sun, sharp drainage, and shelter from frost, and an avocado raises a wide, dark-leaved crown over a yard for decades.
Full sun
Every 3–7 days
USDA 9–11
30–66 ft · 9–20 m
Overview
The avocado is a broad evergreen of the laurel family, native to the warm uplands of Mexico and Central America, carrying glossy, leathery, dark green leaves on a wide, dense crown. In open ground it climbs tall and spreads wide, topping 65 feet (20 m), on shallow roots and brittle, easily split wood that want room and shelter. The fruit hangs as a heavy, pear-shaped berry with rich, buttery flesh, and it stays hard on the branch, softening only after it is picked.
Avocados fall into three races whose leaves and fruit differ in the hand. The Mexican race is the most cold-hardy and bruises its leaves with an anise scent, the West Indian race wants true tropical heat, and the Guatemalan race sits between them, so that lineage sets how much frost the tree takes. Most named cultivars carry the blood of more than one race.
An avocado is slow to come into its own. Its small, pale greenish flowers open in two patterns, type A and type B, and because the two open on different schedules, pollination gets a boost. Plant one, keep its roots dry and its crown out of the frost, and once it settles into bearing it hangs fruit for a household year after year.
Care
The short version: full sun and fast-draining soil come first, since soggy ground rots the roots and kills avocados. Water deeply but let the top half dry between soaks, shield young trees from frost, and feed through the growing season.
Light
Avocados want full sun, ideally six or more hours a day, to fill out a dense, dark-leaved crown. They take a little partial sun, but a tree in real shade stretches lanky and thin and sets far less fruit.
Water
Water deeply but not often, letting the top half of the soil dry before the next soak. Young and fruiting trees need steady moisture, yet avocados hate wet feet, and waterlogged ground rots the fine feeder roots that hold the tree up.
Soil
Give them deep, well-drained sandy loam that never turns to muck around the roots. A pH between 6.0 and 7.0 suits them, and where the ground stays wet, a raised mound lifts the crown clear of standing water.
Temperature
Avocados hold from about 23°F to 95°F (-5°C to 35°C), though the cold end leans on the race. In frost-tender types the tender new flush blackens well before the Mexican-race trees feel it, so match the cultivar to your winters.
Humidity
Average humidity, around 40% to 60%, keeps the leaves comfortable. Avocados are not fussy about moisture in the air, so it needs no attention outdoors.
Feeding
Feed monthly through the spring-to-fall growing season with a balanced fertilizer carrying nitrogen and micronutrients. Avocados lean hard on zinc and iron, and a shortage of either pales and mottles the leaves fast.
Pruning
Avocados need little cutting. Take out dead, diseased, or crossing branches and head back lightly after harvest to hold the height and shape of the crown, but skip heavy pruning, which only costs fruit.
Repotting
Avocados almost always grow in the ground, so repotting rarely comes up. A young container tree can be potted up every 2 to 3 years until it goes into its permanent spot.
Size & spacing
This is a big tree, climbing from 30 to 65 feet (9 to 20 m) tall with a spread to match. Plant it well clear of buildings, foundations, and power lines, and give the brittle, shallow-rooted crown all the room it needs to broaden.
When to plant
An avocado runs on warmth and blackens at a hard freeze. Set young trees out in spring, once the frost danger has passed and the soil has warmed. The small flowers open from late winter into spring, and the heavy fruit swells and ripens on the branches across several months, depending on the cultivar.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Seed can be sprouted indoors year-round in warm conditions, but named cultivars are grafted rather than seed-grown.
- Plant: Spring, after danger of frost has passed and soil has warmed.
- Harvest: Flowers late winter to spring; fruit matures on the tree and is harvested over several months depending on cultivar (e.g., Hass roughly summer to winter).
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Most avocado trouble takes hold at the roots or after a cold night, and the broad leaves show it first, fading, curling, or browning at the edges. Read the canopy closely and you can act before the whole crown thins out. Match what the foliage shows below, then move while it still helps.
Pale, wilting, undersized leaves and a thinning crown
This is Phytophthora root rot, the disease that kills more avocados than any other. The fungus rots the fine feeder roots in soggy ground, so the tree starves and the leaves go pale and small and the canopy thins even under steady watering. Fix the drainage first, ease off the water, and dig in coarse mulch kept clear of the trunk.
Fix:
- Improve drainage and stop overwatering
- Apply phosphite (phosphonate) treatments
- Replant or topwork onto tolerant rootstocks using certified disease-free stock
- Maintain coarse wood-chip mulch kept several inches off the trunk and apply gypsum
Blackened, scorched leaves and dieback after a freeze
This is frost damage, and the West Indian and Guatemalan types take it worse than the hardier Mexican race. A freeze blackens the soft new growth and burns the leaf margins brown, and whole shoots can die back. Wrap and cover young trees through a freeze, then wait for spring growth before cutting away the dead wood.
Fix:
- Protect young trees with covers, trunk wraps, and overhead irrigation during freezes
- Prune frost-damaged wood only after new growth resumes in spring
Brown, brittle tips and edges on the leaves
Browning that creeps in from the tips and margins of the leaves is salt tip burn, where chloride and sodium build up from salty irrigation water or too much fertilizer. It scorches worst in the dry season. Flush the salt down past the roots with a deep, slow soak, and cut back on the feed.
Fix:
- Leach the soil with deep irrigation
- Reduce fertilizer rates
- Switch to lower-salinity water where possible
Toxicity
The ripe green flesh is the food, but every other part of the tree is a real hazard. The leathery leaves, the bark, the skin, and the big woody pit all hold a compound called persin, dangerous to horses, livestock, and birds above all, and able to sicken cats and dogs. Keep grazing animals and pet birds away from the foliage and fruit, and clear up anything that drops.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
A cat that nibbles the green flesh usually gets off lightly, with some vomiting or loose stool from the persin. The real worries are the rich fat, which can set off pancreatitis, and a swallowed pit large enough to lodge in the gut.
Dogs Mild
Most dogs shrug off a small taste with little more than an upset stomach. Watch the fatty flesh, which can bring on pancreatitis, and keep the hard pit well out of reach, since a gulped seed can choke a dog or block the bowel.
Horses Severe
Horses are hit hard by persin. The classic sign is a swollen, puffy head and neck, often alongside colic, and a serious dose can turn dangerous. Keep them away from the leathery leaves, the bark, and any dropped fruit.
Rabbits Toxic
Persin makes every part of the plant unsafe for rabbits, so none of it belongs in the hutch or run. Keep the leaves, bark, and windfall fruit out of reach entirely.
Livestock Severe
In sheep, cattle, goats, and donkeys the persin bloats the head and throat into a puffed, swollen mass while it harms the heart and lungs. A nursing mother may swell with mastitis besides, so keep such animals well back from the tree and rake off every fallen branch.
Birds Severe
Of every creature, birds are the frailest, and even a nibble can kill. Watch for a slack, jittery bird with its plumage rumpled or torn loose, drawing labored breaths as its heart begins to give out. No morsel of avocado should ever reach a pet bird.
People Flesh safe
The ripe green flesh is the part people eat, and it is a healthy, everyday food. The leaves, bark, and skin are not meant for eating, and a small child should be kept from gnawing on the hard pit.
Keep fallen fruit, pits, leaves, and prunings away from pets and livestock; never feed any part of an avocado to pet birds.
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
A handful of cultivars cover nearly every avocado you will handle, set apart by flower type, the look and feel of the skin, and how much cold the tree withstands.
Hass
A type A cultivar that makes up about 95 percent of California's commercial crop, with thick, pebbly skin that turns from green to black as it ripens and a line traced to a single patented 1935 tree.
Fuerte
A type B cultivar of Guatemalan and Mexican parentage, its skin smooth and green, that was the standard market avocado before Hass took over.
Mexicola
A Mexican-race cultivar prized as one of the most cold-hardy, bearing small fruit wrapped in thin, dark skin you can eat.
How to propagate
An avocado starts two very different ways: a single fat pit splitting open on a windowsill, or a thin cultivar shoot bound onto a seedling stem by a skilled graft.
GraftingDemanding
Spring, during warm weather when the bark slips and growth is active · Grafted trees typically bear in 3-4 years
Grafting is how every named avocado is made. In spring, when the bark slips loose and the tree is in active growth, growers cleft- or tip-graft a slim cultivar shoot onto a seedling rootstock, which keeps the fruit true to type and brings a crop in about 3 to 4 years. It takes a steady hand, but it is the only way to copy a variety like Hass.
SeedEasy
Any time in warm conditions · 5-13 years to fruit, if at all
Sprouting a pit is easy and works any time the weather stays warm, as the fat seed splits and pushes up a single stem, but the result is a gamble. A seedling is genetically variable and may take 5 to 13 years to fruit, if it fruits at all, which is why growers mostly raise seedlings as rootstock rather than for the fruit itself.
Myths
Every scrap of avocado spells death for the family dog or cat.
For a dog or cat, the persin packed into the buttery flesh rarely brings on more than a passing bout of stomach upset. The graver threats are pancreatitis from that fat-heavy pulp and the big, hard pit lodging in the gut. It is horses, birds, and grazing stock that stand in real peril.
Dangle a pit in water and it grows fruit matching the tree it came from.
A seedling grown from that fat pit is a genetic toss-up and may take 5 to 13 years to fruit, if it ever does. Named cultivars like Hass are grafted, so they fruit true to type and far sooner.
A solo avocado tree bears a good crop with no partner.
Avocados carry two flower types, A and B, and pairing a type A tree with a type B improves pollination and fruit set. A lone tree can still set some fruit, just less reliably.