Olive trees are among the longest-producing fruit trees there are, and a well-cared-for one can keep bearing for far longer than the person who planted it. Some trees estimated at many centuries old still carry crops today.1PubMed Central. Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location In practice, a tree’s fruiting life depends less on its age than on how it’s grown, how crowded it is, and the conditions it lives in.
When a Young Olive Tree Starts Bearing
Olives planted with moderate spacing usually begin bearing a worthwhile crop in their fourth year after planting.2Florida Olive Council. General Cultivation and Production Information They reach their maximum yield around the ninth or tenth year.3Florida Olive Council. General Cultivation and Production Information The first few years are mostly about building roots, trunk and branches, so a few scattered olives before year four are a bonus. The rootstock a tree is grafted onto can also shape its size and yields over many years.4Journal of the American Society for Horticultural Science. Some Rootstock and Interstock Influences in the Olive (Olea europaea L.) cv. Sevillano
Nursery trees are often one to three years old, so part of the wait may already be over. Larger, older nursery stock usually fruits sooner after planting than small starter plants. Seed-grown trees can take longer to bear and may not produce the same fruit as their parent.
Strong new shoots each year are a good sign, since they are the wood that will carry flowers. Olives flower in spring on growth made the previous year, so clusters of tiny cream flowers are the first signal. Heavy flowering in early years often sets few fruit, and that’s normal. Keeping pruning light in these years lets the tree build its fruiting framework faster, and steady watering through the first dry seasons helps, because a stressed tree spends its energy on survival instead of flowers.
Potted olives can fruit, but limited root space usually means smaller, less regular crops. An indoor tree kept warm all winter may flower poorly, a problem tied to the winter chill discussed below.
If a mature, well-flowering tree sets little fruit, a second variety growing nearby is one possible fix. Most olives set better fruit with a pollinating neighbor, though some are self-fertile enough to crop alone.
How Many Years an Olive Tree Keeps Producing
In well-managed irrigated groves, older plantings yielded just as well as younger ones, with no general drop with age.5PubMed Central. Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location Three olives in Jerusalem’s Garden of Gethsemane, estimated at 800 to 900 years old, still bear fruit.6PubMed Central. Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location Other trees in Israel are likely at least 200 to 300 years old and still producing.7PubMed Central. Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location
The olive tree of Vouves on Crete is thought to be about 2,000 years old and still produces olives.8Olive Oil Times. Gethsemane Olive Trees Among World’s Oldest It was grafted with a variety called ‘Tsounati’, and that graft keeps it productive.9Wikipedia. Olive tree of Vouves Olive wood lacks clear growth rings, though, so ages like these are rough estimates.10Olive Oil Times. Study Questions the Accuracy of Olive Tree Dating Methods One expert concluded that a scientifically sound age for very old olive trees can’t currently be determined.11Olive Oil Times. Study Questions the Accuracy of Olive Tree Dating Methods
Very old olives are often hollow, split or made of several fused trunks, so the living tree can be a much-renewed shell of the original wood. Because olives regrow from the base and from shoots, a tree can replace failing wood over time. One with a decayed core can still carry a healthy crop on the living wood around it, which is why a damaged old tree is rarely a lost cause. The long-lived trees were also mostly kept alive by people who pruned them, cleared competing growth and sometimes grafted them.
Commercial guidance gives well-maintained trees with room to grow a productive life of about 40 years.12Florida Olive Council. General Cultivation and Production Information That figure reflects when growing for profit stops paying, not when a tree physically stops fruiting. A healthy home tree has no reason to be removed at that age. A better test is recent behavior: does it still make new shoots, flower and set fruit in at least some years? A tree that has grown tall and shaded itself may fruit only at the top, and that is a pruning problem, not old age.
Why Olive Trees Skip Years or Don’t Fruit
Olives often swing between heavy crops and light ones, which growers call alternate bearing.13Acta Horticulturae. Mechanisms Regulating Alternate Bearing in Olive and Other Tree Crops A big crop uses so much of the tree’s energy that it needs a year to recover.14ESAO. The olive tree as domesticated plant During a heavy year the tree grows fewer, shorter shoots, leaving fewer places for next spring’s flowers.15Acta Horticulturae. Mechanisms Regulating Alternate Bearing in Olive and Other Tree Crops A heavy crop can also make flower buds drop and stop buds from opening the next spring.16Acta Horticulturae. Mechanisms Regulating Alternate Bearing in Olive and Other Tree Crops The cycle often starts with a bad weather year that ruins one crop, which triggers a huge bloom the next year.17Acta Horticulturae. Mechanisms Regulating Alternate Bearing in Olive and Other Tree Crops In one long-term trial, trees that got no phosphorus fertilizer swung harder between on and off years.18PubMed Central. Long-Term Impact of Phosphorous Fertilization on Yield and Alternate Bearing in Intensive Irrigated Olive Cultivation
At home, you can soften the swings. In a heavy-flowering spring, remove some of the young fruit soon after it sets, so the tree spends less on this year’s crop and keeps energy for next year’s shoots. Thinning only pays off when the tree is clearly overloaded; in a light year there is nothing to thin. Even watering through summer and a balanced feed that includes phosphorus help the tree recover while carrying fruit. Picking earlier instead of leaving olives hanging into winter frees the tree sooner from the cost of ripening them.
Most olives need a period of winter cool to form flowers.19Botanical Gazette. Effect of Different Amounts of Winter Chilling on Fruitfulness of Several Olive Varieties In an experiment, trees kept in a warm greenhouse all winter produced no flowers at all.20Botanical Gazette. Effect of Different Amounts of Winter Chilling on Fruitfulness of Several Olive Varieties Flowering is thought to work best around 11°C (52°F), while temperatures below about 6°C (43°F) don’t seem to count toward the chill.21PubMed Central. Studying Parameters Affecting Accumulation of Chilling Units Required for Olive Winter Flower Induction The variety ‘Arbequina’ has flowered and fruited well even without these cool temperatures.22International Journal of Fruit Science. Is Chilling a Prerequisite for Flowering and Fruiting in ‘Arbequina’ Olives?
Warming can hurt in other ways too. Experimental warming of 4°C brought flowering earlier, caused more flowers to fail and set less fruit.23Scientia Horticulturae. An approach to global warming effects on flowering and fruit set of olive trees growing under field conditions The same warming gave smaller olives with less oil.24Scientia Horticulturae. Global warming effects on yield and fruit maturation of olive trees growing under field conditions
To work out what happened to your tree, start with what it looks like. Healthy leaves and good new growth but no flowers point to an off year or too little winter cool, since both leave a tree looking fine. If flowers appeared but few olives followed, look at the weather during bloom, because heat or dry wind then can make flowers fail. Scorched leaves or dying branches suggest disease or drought, a different problem from a skipped year, covered below. After several mild winters with no flowers, a variety like ‘Arbequina’ may suit your climate better, though the cause could be something other than winter warmth.
Bringing an Old or Overgrown Tree Back Into Production
Olives have a swollen base that stores starch and nutrients.25Land Arch Concepts. Olive Tree Management: Environmental Profile for the Olive Tree That’s why the tree can regrow even after fire or frost kills the top.26Land Arch Concepts. Olive Tree Management: Environmental Profile for the Olive Tree
Hard pruning to renew a tree pays off. In one trial, every rejuvenation method beat traditional pruning, which gave about 5.8 kg (13 lb) of olives per tree.27Acta Horticulturae. Effect of Four Rejuvenation Pruning Methods on Olive Tree Vegetative Growth and Yield Removing one main branch per year did best, averaging about 24.7 kg (54 lb) per tree.28Acta Horticulturae. Effect of Four Rejuvenation Pruning Methods on Olive Tree Vegetative Growth and Yield Fruit from rejuvenated trees was also bigger.29Acta Horticulturae. Effect of Four Rejuvenation Pruning Methods on Olive Tree Vegetative Growth and Yield In a crowded hedgerow grove cut hard back, yields recovered in the second year and peaked in the third.30Acta Horticulturae. Effect of rejuvenation pruning on the olive yield of different cultivars in a super-high-density olive orchard
To renew a tree one limb at a time, choose the oldest, least productive main limb and cut it close to its base in late winter or early spring, before growth starts. Vigorous new shoots will grow from near the cut over the following season. Keep one or two strong ones to become the replacement limb. Repeat with another old limb each year, so the rest of the tree keeps bearing and you’re never left without a crop. Cutting everything at once should be reserved for a badly damaged tree, since the gradual method did best in the trial.
Cutting back to the stump has its place. If frost or fire has killed the top, the swollen storage base can send up new shoots, so a tree that looks dead above ground may not be finished. Cutting a healthy tree down to ground level gave less fruit than gradual renewal, so save a hard cut for when the top is dead or can’t be saved.
What Can End an Olive Tree’s Fruiting Life
Densely planted groves may need thinning or replanting after 10 to 15 years.31Florida Olive Council. General Cultivation and Production Information Their vigor is hard to control, which shortens orchard life.32Plantae®. Intensive and super-intensive olive growing – irrigation Some dense hedgerow groves have kept yields steady for 14 years with the right variety and spacing,33PubMed Central. Cultivar and Tree Density As Key Factors in the Long-Term Performance of Super High-Density Olive Orchards but that takes careful management most home gardeners aren’t set up for. At home, giving a tree room matters more for a long fruiting life than almost anything else.
Plan for the full-grown canopy when you pick the spot, because a tree squeezed against a wall or another tree will lose fruiting wood to shade. If trees you already have are crowding each other, removing one or thinning branches is a better fix than waiting for yields to fall.
Disease can end fruiting outright. In southern Italy, the bacterium Xylella fastidiosa has left susceptible trees with scorched leaves and no olives at all.34Agronomy. Coexistence between Xylella fastidiosa Subsp. pauca and Susceptible Olive Plants in the Salento Peninsula (Southern Italy) Sudden leaf scorch with branches dying back is worth reporting to your local agriculture extension service instead of guessing at the cause. Buying trees from reputable nurseries lowers the chance of bringing a disease like Xylella into your yard, and where it’s present, local guidance on plant movement and monitoring matters.
Climate matters as well. Long-term olive yields depend heavily on rain during flowering and fruiting as well as on temperature.35Communications Earth & Environment. Olive production in the 21st century will be threatened by water stress and declining solar activity Repeated drought and hotter seasons can cut crops even on old, healthy trees. Water deeply during flowering and fruit set in dry spells, and mulch and deep, infrequent watering help a tree cope.