Popular as an ornamental potted plant for the home or patio, the olive tree (Olea europaea) is a huge cash crop in many parts of the world. And if you live in USDA Zone 10 or 11 (or an equivalent climate), you can also grow olive trees in the landscape.
While olive trees do quite well in containers, there is a limit. Potted olives rarely flower or set fruit and usually have a much shorter lifespan than those grown in the ground. In other words, only olive trees planted in the ground will likely complete a full life cycle.
In this article, I’ll walk you through 6 important olive tree growth stages. You’ll learn a bit about growing olives at home and what goes into cultivating this crop on a larger scale.
Conditions for Growing Olives
Olives come from evergreen trees native to the Mediterranean. These trees are incredibly long-lived, with the average lifespan being around 500 years in ideal growing conditions! Most outdoor-grown olive trees range from 10 to 40 feet tall. (Container-grown trees stay much smaller and typically only live about ten years.)
Olive trees require warm temperatures and plenty of sunlight. Aim for at least 6 hours of sun exposure per day. They are super tolerant of drought conditions and need fast-draining soil to thrive. According to the University of California, you can get away with watering olive trees once a month in the summer.
Many gardeners grow olives in containers rather than in the ground because these trees cannot handle cold temperatures. Most mature trees can survive brief periods of 15°F, but these conditions can be fatal to immature or otherwise stressed trees.
I don’t recommend planting trees that your native soil can’t support. In other words, you won’t want to rely on soil amendments like fertilizer to keep your olive tree happy and healthy. Conduct a soil test before planting to determine whether or not your chosen site is suitable for an olive tree.
Olive Tree Growth Rate
Olive trees grow relatively fast early on, reaching their maximum height after about 15 years. During this time, the growth rate can range from 2 to 12 inches annually. This rate largely depends on the growing environment and the tree’s overall health.
While growth naturally slows after those first 15 years, olive trees never stop growing. However, an olive tree won’t get much taller after this point.
Growth Stages of Olive Tree
There are many different kinds of olive trees out there. Most have been carefully bred for the quality of their fruit.
All olive trees take about three years on average to produce their first crop. Subsequent harvests will grow until the tree reaches its maximum productivity.
The natural olive tree life cycle starts with a seed. However, remember that many commercially grown trees are started from vegetative cuttings. Not only do cuttings tend to establish themselves slightly faster, but this method also makes it easy to clone the genetics of a given tree and its fruit.
1. Seed Germination
Growing an olive tree from a seed starts with a fresh olive pit. Note that the olives sold in grocery stores have been treated and will not germinate.
The pit itself is not the seed but rather a hard shell protecting the more delicate olive seed inside. Mother Nature knows how to work around this, so the seed will sometimes sprout even if the pit around it is left intact. But I still recommend carefully cracking the outer hull to improve germination.
Most olive trees require some degree of cold stratification to trigger germination. You can accomplish this by exposing the seed to 30 to 60 days of temperatures below 50°F before planting.
On a chemical level, germination starts when the seed absorbs a certain amount of moisture. Soaking the olive pit in water for 24 hours can help speed this process along. Otherwise, the seed will need to slowly imbibe water from the soil around it (which can take much longer).
Once germination begins, cells inside the seed will start rapidly dividing. This results in several key structures, including the radicle, hypocotyl, and cotyledons.
At temperatures between 60 and 70°F, olive seed germination can take anywhere from 21 to 90 days.
Here’s some good news: once an olive tree sprouts, it’s normally smooth sailing for the first year! Olive seedlings can grow up to 12 inches tall in the first year.
This is a period of rapid growth and development. While the tree grows taller, its taproot penetrates several feet into the ground to anchor the tree and pull water and nutrients from the soil.
Although there’s no set time frame when an olive tree is considered a seedling, I think of any tree three years or younger as a seedling or sapling. After those first three years, it’s usually time to transplant the olive tree to a more permanent location.
3. Vegetative and Root Growth
Olive trees have relatively small, narrow leaves ranging from sage green to silver. The leaves are responsible for photosynthesis and contain a number of biochemical compounds (many of which are still being researched).
Remember that the olive tree is working just as hard to produce a strong and expansive root system as it is to increase its above-ground size early in life. Olive trees typically have shallow root systems — this may be an adaptation to access water quickly after sparse rainfall — and remain within the top 5 feet of soil.
While the taproot is dominant for the tree’s first few years, the tree’s lateral root system eventually takes over. These roots grow at about the same rate as the parts of the tree above ground.
In most regions, olive trees bloom from March to May. Only a small number of flowers (up to 3% on average) each year will develop into mature fruit. The rest will drop from the tree after blooming.
Olive trees have small white flowers that form inflorescences of up to 30 individual blossoms. Flowers develop from small yellow-green buds that normally emerge near the ends of the stems.
Many olive flowers self-pollinate without any help from insects or the wind. However, several varieties require cross-pollination. These varieties must be paired with a second tree to produce fruit. Wind is the primary purveyor of cross-pollination between olive trees.
5. Fruit Development
Even pollinated flowers will drop their petals shortly after opening. A small cup-like structure will remain on the inflorescence stem. This is where you’ll see the olive fruit emerge.
Immature olives are green but gradually turn pink-red and then purple or black as they mature. Fruit development and maturation occur throughout 6 to 8 months (or about 180 to 250 days!).
When to Harvest Olives
Olives aren’t only harvested when fully ripe. Rather, whether you end up with green or black olives comes down to when you decide to pick the fruit from your tree. You’ll also need to determine how to use your olives before picking.
Green olives are usually picked in late summer. A good way to check if green olives are ready to harvest is by squeezing the juice from a couple of fruits. The olives will produce a cloudy liquid if ready to go.
You can monitor the ripeness of most later olives just by watching the color of the fruit change. The olives will blush as they age, eventually turning purple or black.
For more information about plant life cycles, here’s an article about Wheat Growth Stages.
FAQs Growing Olives
Which olives grow the fastest?
If you’re looking for an olive tree for your garden that will fill out quickly and produce fruit within its first couple of years, there are a few varieties worth planting. ‘Frantoio’ is often regarded as the best fast-growing olive tree for home and commercial growing.
Does it take two olive trees to produce fruit?
Most olive trees are self-fertile. You can plant just one tree, which will pollinate itself to produce fruit yearly. If you want to grow one of the varieties requiring cross-pollination, you’ll need to plant at least two trees to reliably produce any fruit.
Do olive trees need a lot of water?
Olive trees are relatively drought-tolerant once established. You may need to water deeply once a month during particularly hot or dry weather. Note that newly planted trees need regular watering until their root systems can fill out.
- The University of California Caring for Olive Trees
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.