Tree · Rutaceae
Orange
Citrus × sinensis
Offer it full sun, warmth, and well-drained soil, and a sweet orange tree loads its branches with bright fruit for decades.
Full sun
Every 7–14 days
55–100°F · 13–38°C
USDA 9–11
Overview
The sweet orange is the most widely grown citrus in the world, an evergreen tree whose glossy, deep green leaves hold a light and give off a sharp citrus scent when crushed. Its white blossom opens in small, waxy, five-petaled stars that carry a heavy fragrance, and its fruit ripens from green to a firm globe of pebbled orange rind through the cool months. It belongs to the rue family beside lemons and limes, and it thrives where winters stay mild, roughly USDA zones 9 to 11, though a large pot lets a frost-prone garden shelter it indoors.
An orange is a long-lived tree that grows at a moderate pace to 20 to 30 feet (6 to 9 m), forming a dense, rounded crown of overlapping evergreen leaves. The fruit sits in a thick, oil-flecked rind over pale, juice-swollen segments, and it colors slowly across fall and winter, so a single branch often carries white blossom and heavy, ripening oranges together. The tree lives and bears for decades once it settles.
Almost every orange begins as a graft, a chosen variety joined to a tough rootstock, the union often visible as a slight swelling low on the trunk where the two woods meet. That grafted origin is why a seed from your breakfast will not repeat the same fruit. Matched to the climate and given sun and steady water, the tree fills out into glossy foliage and bright fruit.
Care
The short version: bright full sun, warmth, and crumbly well-drained soil, watered deeply but seldom, with a balanced citrus feed all through the growing months.
Light
Oranges want full sun, ideally 8 or more hours a day, which deepens the leaf color and sweetens the fruit. They tolerate a little afternoon shade, but the more sun the glossy canopy takes in, the heavier and sweeter the crop of rounded fruit.
Water
Water deeply but not often, letting the top half of the soil dry between drinks, which usually means every 7 to 14 days. Young and container trees drink more, while an established tree in the ground handles dry spells; a thirsty tree shows it first in dull, drooping leaves. Soggy, waterlogged soil is the one thing an orange will not forgive.
Soil
Plant in well-drained sandy loam where water never pools around the roots. A pH between 6.0 and 7.5 keeps the leaves a healthy green, and good drainage matters far more than the exact soil type.
Temperature
Oranges grow well from about 55°F to 100°F (13°C to 38°C) and want a frost-free spot. A hard freeze splits the wood and pits the fruit, so a tree near the edge of its range earns its keep in a pot that moves indoors for the cold.
Humidity
Average humidity of 50% to 70% keeps an orange comfortable, the kind of air most warm regions provide on their own. A tree brought indoors for winter appreciates a little extra moisture in dry, heated rooms, where the leaf tips can otherwise brown.
Feeding
Feed with a balanced citrus fertilizer that carries micronutrients such as iron, zinc, and manganese, the elements that keep the foliage a full, even green. Apply it through the growing season, from spring into late summer, and ease off as the weather cools.
Pruning
Oranges need little pruning. Take out dead, damaged, or crossing wood and snap off any suckers that sprout below the graft, since their leaves are often coarser and thornier than the canopy above, working in late winter or early spring before the new flush.
Repotting
A container tree wants a fresh, larger pot every 2 to 3 years. Roots circling the pot, water running straight through, or slowing growth with yellowing leaves all tell you the tree has outgrown its home.
Size & spacing
A standard orange tree reaches 20 to 30 feet (6 to 9 m) tall and spreads 12 to 20 feet (3.6 to 6 m) across into a broad, leafy dome, so give it open room away from buildings and other trees.
When to plant
An orange tree wants warmth and cannot take a hard frost. A new tree set out in spring, once the last freeze has passed, opens its white blossom the following spring, and the fruit swells and colors from fall through winter and into spring depending on the variety.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring after all danger of frost has passed
- Harvest: Blooms in spring; fruit ripens fall through winter and into spring depending on cultivar
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Most orange tree trouble shows first on the tender new leaves and the fruit, where the color and texture change earliest. A few of these are insects you can manage, but two are serious diseases worth catching early. Match what you see below, then act before it spreads through the rest of the tree.
Blotchy yellow leaves with small, lopsided fruit
Leaves smeared with uneven yellow blotches, next to small, lopsided fruit that tastes bitter, point to citrus greening, or huanglongbing, the most serious disease a citrus tree can carry. A tiny insect, the Asian citrus psyllid, moves the bacterium from tree to tree, and once a tree holds it there is no cure. Remove and destroy the tree to spare the ones nearby, and report it to the local agricultural office.
Fix:
- There is no cure; remove and destroy infected trees to reduce spread
- Control Asian citrus psyllid populations
- Report suspected cases to local agricultural authorities
Raised tan corky lesions circled by yellow halos
Rough, raised lesions the color of tan cork, each circled by a yellow halo, break out across leaves, twigs, and fruit and mark citrus canker, a bacterial disease. It travels on wind-driven rain and on wet hands. Strip off and destroy the marked wood and fruit, and use a copper spray where the rules allow it. Many regions treat canker as reportable, so check the local quarantine before moving anything.
Fix:
- Remove and destroy affected plant material
- Apply copper-based sprays where permitted
- Follow local quarantine and reporting requirements
Sticky coating, black sooty mold, and stem-crusting bumps
Small hard bumps cling to the stems and leaf undersides and refuse to rub off, and those bumps are scale insects. Below them the leaves turn sticky and blacken with sooty mold, both fed by the honeydew the scale drips. Coat them in horticultural oil and cut away any twig crusted thick with them, and watch for the ants that tend the scale and chase off its predators.
Fix:
- Apply horticultural oil to smother scale
- Prune heavily infested twigs
- Conserve natural predators and parasites
Thin silvery mazes tracing the crinkled newest leaves
Thin silver lines twist and loop across the youngest leaves, left by the citrus leafminer as its larvae burrow through the soft new flush. A mature tree grows straight past the marred leaves, so they can stay. On a young tree, hold back the tender growth that pulls the moth in, and horticultural oil handles the mining when it turns heavy.
Fix:
- Tolerate light damage on mature trees, which usually outgrow it
- Avoid excess nitrogen and pruning that stimulate frequent tender flush
- Use horticultural oil on young trees if needed
Toxicity
The juice-filled flesh of an orange is a safe, healthy food for people, but the rest of the plant is another matter. The pebbled peel, the glossy leaves, and the seeds hold essential oils and psoralens that upset a pet's stomach and can leave the skin touchy in sunlight. Keep peels and prunings away from cats, dogs, horses, and other animals, and offer only a little flesh as a rare treat.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
The oils held in the peel and leaves usually set a cat drooling, then bring on vomiting and a bout of diarrhea. A cat that eats a lot may turn dull and listless, and the psoralens can leave its skin touchy in sunlight.
Dogs Mild
A dog that chews the peel or leaves tends to get an upset stomach with vomiting and loose stools. A larger helping saps its energy, so its own treats are the better offering.
Horses Mild
The oils and psoralens in the leaves and rind can unsettle a horse's gut and dull its mood. Keep prunings and peels out of the paddock, where a curious horse might otherwise nibble them.
Rabbits Mild
Citrus leaves and peel carry too much essential oil for a rabbit's delicate digestion and can leave it off its food with soft stools. A tiny scrap of flesh now and then is the most a rabbit should ever have.
Livestock Mild
Goats, sheep, and cattle may pick at fallen leaves or peel, which can bring on mild stomach upset. Clear citrus trimmings from grazing areas so the animals are not tempted to fill up on them.
Birds Caution
The oils concentrated in the peel and leaves are best kept away from pet birds, though a small taste of the flesh is generally fine. Offer only a little seedless flesh and skip the rind.
People Flesh safe
The juicy flesh is a healthy everyday food with no risk. Leave the peel, leaves, and seeds out of the bowl, since their oils can sting the mouth and stomach.
Keep peels, leaves, and seeds away from pets; the fruit flesh in small amounts is likely to cause at most minor stomach upset.
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
Hundreds of orange varieties exist, differing in the color of the flesh, the amount of seed, and the season they ripen. The few below are the ones you are most likely to grow or recognize.
Valencia
A late-season juicing orange picked from spring into summer, prized for its nearly seedless flesh and abundant juice.
Washington Navel
A seedless eating orange known by the small second fruit, the navel, cupped into a puckered dimple at its blossom end.
Hamlin
A cold-hardy, early-season juice orange, raised in great numbers across Florida's groves.
Blood orange (Moro)
Its flesh deepens to a dark crimson once cool nights draw out the anthocyanin pigment.
How to propagate
Oranges are nearly always grafted, which secures the fruit and a hardy root, though a tree can be grown from seed if you have years to spare.
GraftingModerate
During active growth in spring to early summer when bark slips easily · Several months to form a union; 3 to 5 years to begin fruiting
Grafting is the usual way to raise an orange, in commercial groves and home gardens alike. Do it in spring or early summer, while the bark peels back easily from the wood, and the union knits over a few months. It yields fruit that matches the parent along with the cold and disease tolerance of the rootstock, though the young tree still needs 3 to 5 years before it begins to bear.
SeedEasy
Sow fresh seed in spring · Germinates in a few weeks but can take many years to fruit
An orange grown from seed is easy to start but slow to reward. Press a fresh seed into soil in spring and a shoot pushes up within a few weeks, yet the tree can take many years to fruit and often will not come true to the parent. For that reason seed mostly raises rootstock or serves as an experiment.
Myths
A fruit that people enjoy safely can be no threat at all to cats and dogs.
The ASPCA lists orange as toxic to cats and dogs, because the peel, leaves, and seeds carry essential oils and psoralens that upset the stomach. The juicy flesh is far gentler, yet even that should be no more than a small, occasional treat for a pet.
The seed inside a store-bought orange yields a tree matching its parent that bears fruit within a year or two.
Sweet oranges are almost always grafted onto a rootstock rather than raised from seed. A seedling can take many years to bear and often will not match the parent, which is why a seed-grown tree mostly becomes rootstock or a curiosity.