Have you ever wondered how olive trees grow or how long they live? In this article, we will be looking at the life cycle of an olive tree, which is important to understand if you want to grow these wonderful plants.
We’ll begin by looking at how olive trees progress from germination to maturity and work our way up to the flowers and fruits that olive trees are grown to produce.
The Life Cycle of an Olive Tree
Olive trees are believed to have been among the first trees to be cultivated by man. A sturdy, attractive tree that produces the fruit we love, the olive tree can live for hundreds of years. While slow growing, they are relatively simple to grow, hence their popularity.
In this section, we will talk about the life cycle of the olive tree from germination to maturity.
Olive trees are more often than not grown from cuttings (see our informative article here.) This is the easiest method. However, we want to look at growing from seeds, otherwise known as ‘pits.’ These are the hard seed matter within the olive.
Our first key point is that you will not succeed in germinating an olive plant if you use fruit bought from the store. It must be fresh and from the tree to be fertile. Pick fruit that is in good condition and ripe, preferably not from the ground.
The expert method involves soaking the fresh olives in water overnight, then breaking the olives and removing the pits. It is recommended that you take a pinch out of the end of the pits for more chance of success and then soak the seed in water for another night.
Olive pits should then be sown. These are plants that grow in the Mediterranean climate and prefer a mix of sand and seed compost. We recommend you sow several seeds, as success is not guaranteed!
Put them in the soil – not too deep – and keep them in the shade with the top moist. Bear in mind that olives take a while to germinate. You may see signs within a few weeks, but it can take up to six weeks or more. Once you have seedlings, keep them as they are and look to transplant them in the autumn.
That’s your first stage – germination – complete, and it can be frustrating when you go to the trouble of preparing pits for growth, and nothing happens. Do persevere, for there will be one at least that springs into life.
Olive tree seedlings do need some care. Depending upon where you are in the world, you may find that a heat mat and a cold frame are of great help. Keep the seedlings out of the hot summer sun – they will thrive when they mature but may not when in their infancy – and in a shady area.
Seedlings grow slowly. The olive tree doesn’t race into life but approaches it gradually. Seedlings are best grown and cared for in pots or other containers. Many people keep their olive trees pot-bound, but they do grow best to maturity in the ground.
Water your pots when the soil gets dry, and make sure it is thoroughly soaked. Olive trees in pots will need to be watered more often than those in the ground.
Now you have germinated olive pits successfully and are caring for seedlings, we need to look at the vegetative growth stage that follows.
You will see the growth of the olive tree you have propagated as you follow its progress. If you leave your tree in the pot, it will grow more slowly than in the ground. Don’t expect your seedlings to become fully-fledged trees quickly.
It can take a few years for notable growth to be seen. As we have said these are slow-growing and long-lived trees. Be aware that some olive trees are ‘fruitless.’ These are grown as ornamental trees rather than for harvesting.
You will note two different types of growth: flower buds and vegetative growth. The latter is the formation of new leaves. Both are part of the phenological process, as we shall see later on.
To continue our look at the olive tree’s life, let’s assume you have a tree that is close to maturity. What should you expect?
The olive tree remains relatively dormant during the colder months. Come the warmer days of spring, and you’ll begin to see your trees sprouting buds. The olive flower follows the tree in being slow to open, but when it does, it is a delightful sight.
Floral clusters will open across the tree, and it is at this point that the fruiting process begins. You will see a difference in flowers and fruit year to year. This is because varied weather conditions influence how many flowers the tree produces.
Once the flowers are done, the petals naturally fall to the ground – and there you will see your olives! Olives continue to grow in size and usually reach maturity in the autumn months.
It is traditional to pick olives when they are still green – it’s often forgotten that green and black olives are the same fruit, with the black variety having ripened fully – and to pick them directly from the tree.
So, you now have a mature and fruiting olive tree – what else do you need to know? We’ll be looking in more detail at the growth stages of the mature tree in a moment, but before we move on, here’s a quick look at what to expect from your mature olive trees.
When does an olive tree reach maturity? An olive tree will grow at the rate of around 12 inches every year. The tree remains a juvenile until it is perhaps 15 years old or even more. As mentioned, this is a long-lived tree.
A fully mature olive tree can reach 15 meters tall – around 50 feet – and is a broad, attractive tree that is instantly recognizable. Your olive trees may need pruning – our article on this detail explains more – if you want to keep them in good shape, but apart from that, maintaining olive trees is not difficult once they reach maturity.
Now we want to get a little more scientific and talk about what is known in the growing industry as the ‘phenological phases’ of olive tree growth. We have covered this area above, but we feel it may be interesting to recap and maybe expand a little.
Olive Phenological Phases
Phenology is the study of cycles in the natural world. In this case, we are interested in the phenological stages of the olive fruit. We’ve described the beginnings of the tree up until maturity, so we need to look at the annual cycle of fruiting. Let’s get started!
The annual phenological cycle of the olive begins in the spring – March and April in its natural habitat – with the sprouting stage. This can be observed by looking for buds, which form around this time. These will initially be seen as green growth and are the beginning of the reproductive process of the tree, which results in the fruit.
The buds will form into either flower clusters or leaves. Leaf development – vegetative growth – will be noted in the form of regular olive tree leaves sprouting from the branches.
Appearance of Flowers
The first appearance of flowers on the olive tree will occur at the same time as the leaves develop. Buds that do not become leaves will form flower clusters. This is the continuation of the reproduction stage of the tree, which will eventually become the olive fruit. Flowering is the next stage.
Your olive trees will become adorned with many flowers as the buds open. At this point, the flowers need to be fertilized. Only fertilized flowers can become fruit.
Flowering will begin in the month of May. A flower cluster will last only a week, and the entire flowering process will last three weeks or more.
What is interesting at this point is that very few of the flowers will bear fruit. Olive trees are generally self-pollinating, although it is not unusual for growers to plant flowers and other plants to attract pollinators.
This is important as the more fertilized flowers, the more fruit will be borne by the tree. In fact, it is estimated that a mere 2% of maximum flowers will bear fruit, and this is why olive trees produce many flower clusters.
Once the flowering period is over, you will begin to see the new olive fruit in its place. This is an interesting phase in the phenology of the olive. This will occur during July and August when it is notably hot and dry.
There is a phase known as ‘fruit set.’ This is where the olive tree releases some of the young olives to fall from the tree. The stronger fruit remain and are able to feed and grow.
The stage of fruit development is the most fascinating and is a wonder of nature. The olive tree deals with the heat and lack of water by closing what is known as ‘stomata’ – tiny pores on the leaves that allow for evaporation – thus preserving the water within to help feed the fruit.
The olives grow until a certain size, at which point they are often picked when still green.
Green olives are those that have been picked for use before they are fully ripe. Left on the tree, the olives will turn yellow or pink before reaching the deep red or black coloring of ripe and mature olives.
The phenological phases are done, and the olive tree now waits until next spring to begin again.
The average lifespan of an olive tree is between 300 to 500 years! There are trees that are believed to be 1500 years old, but it is difficult to clarify.
Grown from seed, successful germination will become a mature tree at around 12 to 15 years old. Juvenile trees will add 12 inches each year. As for the fruit, from the shooting stage in spring until the fruits become large enough to harvest and begin to ripen will take around three to four months.
This is a long-lived species. There are instances in which olive trees have lived for 1000 years. Indeed, the oldest tree still living is believed to be 1500 years old.
We hope this article has been of interest to you and enlightened you as to the lifecycle of the fascinating olive tree and the valuable fruit that they produce.