Tree · Oleaceae
Olive
Olea europaea
Give it full sun, lean soil, and a dry root run, and the olive thrives for generations.
Full sun
Every 14–30 days
USDA 8–11
20–49 ft · 6–15 m
Overview
The olive is a slow-growing evergreen tree of the Mediterranean, at home in hot, dry country where little else fruits. It has been cultivated for thousands of years for its oil and its fruit, and a single tree can live for centuries. Plant one and you are planting for the long haul, not the season.
What an olive asks for is mostly the absence of things. It wants full sun, sharp drainage, and lean soil, and it shrugs off poor, rocky, and chalky ground that would starve a fussier tree. Give it too much water or rich, soggy soil and it sulks. Hold back, and it rewards you.
There is one quirk worth knowing up front. The fruit you pull off the branch is inedibly bitter raw, and it has to be cured before it's any good. The tree also needs a touch of winter chill to flower well, so it suits warm-temperate gardens rather than the tropics.
Care
The short version: full sun, sharp drainage, and lean soil, with deep but infrequent watering once the tree is established. Skip the rich feeding and the standing water, and prune in late winter to keep the canopy open.
Light
Olives are sun lovers and want full sun all day to fruit well. They'll tolerate a little partial sun, but a shaded tree grows lanky and sets a thin crop, so give it the brightest spot you have.
Water
Once established, the olive is genuinely drought tolerant and prefers a deep soak every 14 to 30 days over frequent sips. Let the soil dry right out between waterings. Soggy, waterlogged roots are the fastest way to rot a tree that would otherwise live for centuries.
Soil
Drainage matters more than richness here. Olives thrive in well-drained sandy loam and happily take poor, rocky, and chalky ground, across a wide pH of 6.0 to 8.5. What they won't forgive is heavy soil that holds water around the roots.
Temperature
The olive handles real heat, up to about 100°F (38°C), and shrugs off the dry Mediterranean summer. It is more tender to cold, taking only brief dips to around 19°F (-7°C) before the wood is damaged, so it belongs in warm-temperate gardens.
Humidity
Dry air suits the olive fine, and it does best in low humidity around 20% to 50%. Damp, still conditions invite the fungal leaf spots that plague it, so good airflow counts for more than any moisture in the air.
Feeding
Olives are light feeders that grow lean by nature. A single balanced, nitrogen-rich feed in spring is plenty, once a season. Pile on more and you push soft, leafy growth at the expense of fruit.
Pruning
Prune in late winter to early spring, opening the canopy into a loose vase shape so light and air reach the center. Take out suckers, dead wood, and crossing branches. An open tree both fruits better and resists the fungal spots that thrive in dense, shaded growth.
Repotting
Container olives need repotting every 2 to 3 years to stay healthy. Watch for roots circling the pot or pushing out the drainage holes, water that runs straight through, and stalled new growth, all signs the tree has outgrown its home.
Size & spacing
Left to grow, an olive reaches 20 to 50 feet (6 to 15 m) tall with a broad spreading crown. Give it the room to match, around 15 to 30 feet (4.5 to 9 m) of clearance, since it's a tree that settles in for the long term.
When to plant
The olive runs on a slow Mediterranean clock. Set young trees out in spring once the frost has passed and the soil has warmed, look for bloom in late spring, and gather the fruit through fall, from September into November.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: spring after the last frost once soil has warmed
- Harvest: blooms late spring; fruit harvested fall (September to November)
Hardiness
USDA hardiness zones: 8–11
Temperature: down to -12°C
Troubleshooting
Most olive trouble traces back to wet conditions and wounds, whether it's a bacterial gall or a fungal leaf spot. Catch the early signs and a dry-season pruning often settles things. Match what you see below, then act before it spreads through the canopy.
Branches wilting and dying back, often on one side
This is verticillium wilt, a soilborne fungus that invades the tree's plumbing and chokes off whole limbs, often one side at a time. Cut a wilting branch and you'll see the wood stained inside. There's no cure, so remove the dead wood, hold back on water, and never replant olives where the disease has shown up before.
Fix:
- Remove and destroy dead wood
- Avoid overwatering
- Do not replant olives where the disease is known
Rough woody galls swelling along twigs and branches
These tumor-like lumps are olive knot, a bacterial disease that slips in through pruning cuts, frost cracks, and leaf scars, and it spreads worst after wet weather. Cut the infected wood out in dry conditions, well below the galls, and disinfect your tools between cuts. A copper spray after pruning or a frost helps seal the door behind it.
Fix:
- Prune out infected wood in dry weather well below the galls
- Disinfect tools between cuts
- Apply a copper bactericide after pruning or frost injury
Punctured fruit with maggots tunneling the flesh
The puncture marks and cream-colored maggots are the work of the olive fruit fly, whose larvae feed inside the developing fruit. Cut a suspect olive open to confirm, and hang baited traps as harvest nears. Pick promptly, clear every fallen fruit, and turn to approved bait sprays or kaolin clay where the flies are thick.
Fix:
- Harvest promptly
- Sanitize fallen fruit
- Use approved bait sprays or kaolin clay where infestation is heavy
Dark peacock-eye rings on leaves before they yellow and fall
Those sooty circular lesions ringed with a yellow halo are olive peacock spot, a fungus that settles into the lower canopy during cool, wet stretches and triggers leaf drop. Prune to open the tree for airflow and rake up the fallen infected leaves where spores overwinter. A copper fungicide in fall, ahead of the rains, keeps it in check.
Fix:
- Improve air circulation through pruning
- Apply a copper fungicide in fall before rains
- Rake and remove fallen infected leaves
Toxicity
Good news for households with animals: the olive tree is non-toxic and safe to have around pets, livestock, and people. The fruit itself is even edible once cured. The only real hazard is the hard pit, which can choke a pet or block the gut if swallowed whole, so keep fallen fruit picked up.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The olive tree itself is safe around cats and isn't listed as toxic. The one real risk is a swallowed pit, which can lodge in the gut, so sweep up fallen fruit.
Dogs None
Dogs can be around an olive without any poisoning worry. Watch the hard pits, though, since a gulped stone can choke or block the gut, and skip salty cured olives.
Horses Safe
Olive foliage poses no toxic threat to horses grazing nearby. Just keep windfall fruit from piling up, because a swallowed pit is a choking hazard.
Rabbits Safe
The plant is non-toxic to rabbits. A whole pit is far too large and hard for them to handle safely, so keep dropped fruit out of the hutch and run.
Livestock Safe
Goats, sheep, and cattle can browse around olives with no poisoning risk. The hard stones are the only concern, since a swallowed pit can lodge or choke.
Birds Safe
Olives carry nothing toxic to birds, and wild ones eat the fruit readily. The dense pit is the catch, as it can choke a smaller bird that tries to swallow it whole.
People Safe
Cured olives are a kitchen staple and safe to eat, though raw fruit straight off the tree is far too bitter to enjoy. Don't bite down on the hard pit, and watch that small children don't swallow one.
The hard fruit pit is a choking and gastrointestinal obstruction hazard if swallowed, and cured table olives are very high in salt, so neither should be offered to pets.
Varieties
Olive cultivars split mainly into those grown for oil and those grown for the table, with a few bred to drop little or no fruit at all. These are the names you'll meet most often.
Arbequina
A small, self-fertile Spanish cultivar that handles cold better than most and takes happily to oil pressing or container growing.
Mission
A cold-hardy California cultivar that pulls double duty, good for both table olives and pressing oil.
Manzanillo
A widely grown rounded table olive prized above all for canning.
Frantoio
The classic Italian oil cultivar, the one behind so much high-quality fruity olive oil.
Swan Hill
A nearly fruitless, low-pollen cultivar planted where dropped fruit and allergens would otherwise be a nuisance.
Companions
How to propagate
Most olives are propagated from cuttings or grafts so the new tree matches its parent, since seedlings are slow and rarely true to type.
Stem cuttingsModerate
Late spring to summer · 2 to 3 months to root
Cuttings are the dependable way to copy a named olive, since they come true to the parent. Take semi-hardwood cuttings from late spring through summer and root them under mist with bottom heat, and they'll strike roots in about 2 to 3 months.
GraftingDemanding
Spring · One growing season
Grafting is the skilled grower's route for putting a prized cultivar onto a tough seedling or clonal rootstock. Done in spring, a successful graft knits together and takes hold over a single growing season.
SeedDemanding
Fall · Several years to fruiting
Seed is slow and unpredictable, and the seedlings won't match the parent cultivar, so it's used mainly to raise rootstock. Sow in fall and expect a wait of several years before a seed-grown tree fruits at all.
Myths
Olives can be picked and eaten straight off the tree.
Raw olives are punishingly bitter thanks to a compound called oleuropein. Before they're worth eating, the fruit has to be cured in brine, lye, or salt to draw that bitterness out.
Olive trees never need cold weather.
They are cold-sensitive, true, but they still need a stretch of winter chill to flower and set fruit reliably. A winter that stays too warm leaves you with a healthy tree and very few olives.