Depending on the olive variety you choose, some olive trees are self-pollinating and some require a pollinator. Self-pollinating olive trees include Arbequina, Koroneiki, Fantoio, Coratina, Picual; whereas olive trees that require pollinators include Manzallino, Mission, Sevillano.
Olive trees requiring a pollinator may seem like additional work, however, cross-pollination generally improves the fruit set especially when environmental conditions are not optimal. Even so, if it is a self-fruitful olive cultivar, it increases fruit set by cross-pollination.
In this article, you will find relevant information about self-pollinating olive trees, varieties requiring cross-pollination, and an olive tree pollination chart.
Self vs Cross-pollinating Olive Trees
Self-pollinating or self-fruitful or self-fertile olive trees
They do not need other olive varieties to grow next by, a single olive tree is pollinated by the wind or bees. As a result will bear the olive fruits all by itself.
Therefore to obtain a maximum olive yield, it is necessary to associate self-fertile varieties with others that are also good pollinizers.
Cross-pollinating or self-unfruitful olive trees
They need another tree or sometimes two other trees for complete pollination. They should not be the same variety, but a different olive tree variety.
For example, the Manzanillo olive tree may be best pollinated by a Sevillano or Barouni olive variety. Though Ascalono and Mission could also pollinate Manzanillo but with lesser results in crop yield. Also, they all have to blossom at about the same time.
Generally having 2 or more different compatible varieties growing in close proximity 100 feet (30 meters) will facilitate adequate cross-pollination.
Good thing, when olive trees are cross-pollinated (even if it is unnecessary) you benefit from a higher probability of pollination, bigger fruits and higher crop yield of 10% or even more.
|Self-pollinating Olive Tree Variety||Origin Country|
When & How Olive Tree is Pollinated?
The olive tree pollination happens in spring, when the trees blossom.
Pollen from the anthers (the male part of the olive tree flower) has to be transferred to the stigma (the female part of the olive tree flower). Only if the olive tree flower is pollinated successfully, the olive fruit grows. Else, an olive flower is blooming, but not fruiting afterward.
Pollen wind role is very important to not only spread and diffuse pollen grains, but also transfer them fast to reach stigma before they loose their viability.
Also, if an olive tree flowers do well in spring and does not set any fruit afterwards, it may be an indicator that your tree needs a cross pollination with a cross-compatible olive cultivar.
Read more about olive tree flowers and
Why My Olive Tree Is Not Pollinated?
There are multiple factors which can interfere with pollination. Let’s look into several of them:
Olive variety compatibility
If your olive tree is cross-pollinating, you should ensure to plant other varieties compatible with your own variety. Also, they all have to blossom at about the same time.
For example, a Frantoio and a Koroneiki olive trees are not compatible with each other. Similarly a Manzanillo and a Mission trees are not compatible with each other.
Lack of rain or too much rain; high or hot dry winds; spring frost can damage flower buds before they blossom or can be detrimental to pollination during the flowering season.
Also, excessive winter cold or even late-spring frost can kill flower buds and blossoms. For this reason, it is important to choose the right olive tree variety for your climate zone.
For more information read our article where do olive trees grow best.
Different Length of Blooming
The different length of blooming when olive flowers get pollinated depends on variable environment conditions such as temperatures and rains.
For example, the blooming period may be short due to high temperatures with lower possibility of cross pollination. It can start early in spring since thermic conditions are favorable but end up when heavy rains start. Another scenario for a longer blooming period is a mild temperatures and frequent but low rains.
Pests and Diseases
Pest and diseases can be problem for olive flowering and pollination. Not treated olive trees on time may end up losing all flowers and fruit sets.
Fertilize prior Pollination
Prior the spring olive flower an fruit developing season, feed your olive tree with nitrogen and potassium for better crop results. Use only organic fertilizers and natural pesticides if needed.
If you are not sure about the soil condition, it is recommended to test your soil at least once in 2 years in order to ensure relevant nutrition for your olive trees.
Olive Tree Pollination Chart
The dynamics of compatibility in olive varieties are somewhat complex, and many varieties even self-compatible require cross-pollination for a better fruit set.
This is not an exhaustive olive tree pollination chart with main varieties used for cross-pollination:
Under optimal weather conditions at the flowering season with cross pollinators, you can achieve maximum crop yield results.
When you are searching for an olive tree ready to plant in small spaces, consider self-pollinating olive trees varieties in order to enjoy olive harvest every autumn. In case you have the opportunity to plant several olive trees, pick compatible varieties and improve crop yield.
About the intercompatible olive cultivars the best to discuss with a local agronomist or local farmer cause it depends on overlapping factors such as blooming, pollen compatibility and environment conditions. Knowledge on self(in)compatibility is important for the olive tree growers to allow them to better manage newly introduced cultivars in their orchards and for choosing suitable pollinators among the local olive cultivars.
Also, if you have space for other trees to cross pollinate your olive tree and get a higher crop yield. Example, olive trees should be spaced between 6 feet (2 meters) for a high density grove or 18 feet (5 meters) for a traditional grove.
Plant the olive tree where fallen fruit won’t cause a problem – away from decks, driveways, and walkways. Otherwise, get a fruitless olive tree or learn 5 ways to remove olive stains from concrete on pathways.
Olive bloom and pollination by University of California
Cross pollination in olive cultivars – RIRDC publication