Tree · Rutaceae
Orange
Citrus × sinensis
Give it full sun, warmth, and well-drained soil, and a sweet orange tree rewards you with 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 with glossy leaves, fragrant white blossom, and fruit that ripens through the cool months. It belongs to the rue family alongside lemons and limes, and it thrives where winters stay mild, roughly USDA zones 9 to 11. Where frost is a worry, gardeners grow it in a large pot that can shelter indoors for the winter.
An orange tree is a long-term resident. It grows at a moderate pace and can reach 20 to 30 feet (6 to 9 m) in the ground, living and bearing for decades once it settles in. The tree blooms in spring and carries its fruit slowly through fall and winter, so the same branch often holds blossom and ripening oranges at once.
Almost every orange you buy began as a graft, with a chosen variety joined to a tough rootstock that handles cold and disease. That is why a seed from your breakfast won't give you the same fruit. Pick the right variety for your climate, give it sun and steady water, and the tree does the rest.
Care
The short version: full sun, warmth, and well-drained soil, with deep but infrequent watering and a balanced citrus feed through the growing season.
Light
Oranges want full sun, ideally 8 or more hours a day, to ripen sweet fruit. They put up with a little afternoon shade, but the more sun a tree gets, the heavier and sweeter the crop.
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 well. 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 suits the tree, 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 damages the wood and 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.
Feeding
Feed with a balanced citrus fertilizer that carries micronutrients like iron, zinc, and manganese. 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, 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 yellow leaves all tell you it's time to move up a size.
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, 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. Set a new tree out in spring once the last freeze has passed, and it blooms the following spring with fruit ripening 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 new leaves and the fruit. A few of these problems are insects you can manage, but two are serious diseases worth catching early. Match what you see below, then act before it spreads to the rest of the tree.
Blotchy yellow leaves with lopsided, bitter fruit
This is citrus greening, or huanglongbing, the most serious disease a citrus tree can catch. A tiny insect called the Asian citrus psyllid spreads the bacterium from tree to tree, and once a tree has it there is no cure. Pull and destroy the tree to protect your neighbors, and report it to your 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
Corky tan spots ringed with yellow on fruit and leaves
Raised, scabby lesions edged in yellow point to citrus canker, a bacterial disease that spreads on wind-driven rain and wet hands. Strip off and destroy the infected wood and fruit, and reach for a copper spray where the rules allow it. Many regions treat canker as a reportable problem, so check your local quarantine before you move anything.
Fix:
- Remove and destroy affected plant material
- Apply copper-based sprays where permitted
- Follow local quarantine and reporting requirements
Sticky leaves, black mold, and bumps on the stems
The little bumps that won't brush off are scale insects, and the sticky film and black soot below them is the honeydew they leave behind. Wipe them out with horticultural oil and cut away any twig that is crusted over. Watch for ants too, because they farm the scale and fend off the predators that would otherwise keep it in check.
Fix:
- Apply horticultural oil to smother scale
- Prune heavily infested twigs
- Conserve natural predators and parasites
Silvery winding trails on curled new leaves
Those squiggly silver tracks are the work of the citrus leafminer, whose larvae tunnel inside the soft new flush. A mature tree shrugs off the damage and grows right past it, so leave it be. On young trees you can hold back the tender growth that draws the moth and treat with horticultural oil if the mining gets 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 flesh of an orange is a safe, healthy food for people, but it's a different story for animals. The peel, leaves, and seeds hold essential oils and psoralens that upset a pet's stomach and can make 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 essential oils in the peel and leaves usually bring on drooling, vomiting, and a bout of diarrhea. A cat that eats a lot may turn dull and listless, and the psoralens can leave the 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. Bigger helpings can sap its energy, so steer it toward its own treats instead.
Horses Mild
The oils and psoralens in the foliage and rind can unsettle a horse's gut and dampen its mood. Keep prunings and peels out of the paddock where a curious horse might nibble them.
Rabbits Mild
Citrus leaves and peel are too rich in essential oils 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 cause mild stomach upset. Clear citrus trimmings from grazing areas so animals aren't tempted to fill up on them.
Birds Caution
The oils concentrated in the peel and leaves are best kept away from pet birds, even 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, split mostly between eating types and juicing types. These few cover the ones you're most likely to grow or recognize.
Valencia
A late-season juicing orange picked from spring into summer, prized for nearly seedless fruit and outstanding juice.
Washington Navel
The seedless eating orange you know by the little second fruit, the navel, tucked into its blossom end.
Hamlin
An early, cold-hardy juice orange grown widely across Florida groves.
Blood orange (Moro)
Turns its flesh a deep red once cool nights coax out the anthocyanin pigment.
How to propagate
Oranges are nearly always grafted to guarantee the fruit and a hardy root, though you can grow one 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 standard way to grow an orange, both in commercial groves and at home. Do it in spring or early summer while the bark slips easily, and the union knits in a few months. The graft gives you fruit that matches the parent, plus the cold and disease tolerance of the rootstock, though the young tree still needs 3 to 5 years before it starts to bear.
SeedEasy
Sow fresh seed in spring · Germinates in a few weeks but can take many years to fruit
Growing an orange from seed is easy, but it asks for patience. Sow a fresh seed in spring and it sprouts within a few weeks, yet the tree can take many years to fruit and often won't come true to the parent. For that reason seed is mostly used to raise rootstock or simply to experiment.
Myths
Oranges are completely safe for cats and dogs because the fruit is edible for people.
The ASPCA lists orange as toxic to cats and dogs, since the peel, leaves, and seeds carry essential oils and psoralens that upset the stomach. The juicy flesh is far safer, but even that should be no more than a small, occasional treat for a pet.
A seed from a store-bought orange grows a tree just like its parent that fruits in a year or two.
Sweet oranges are almost always grafted onto a rootstock, not grown from seed. A seedling can take many years to bear and often won't match the parent, which is why a seed-grown tree is mostly used for rootstock or for fun.