Olive Oil: The Trees

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Our new house has two olives trees. I heard a StuffYouShouldKnow podcast about olive oil and got excited. “Right”, I thought, “I am going to make olive oil”.


Reading up a little about olive trees, I got to the bit about the different cultivars/ varieties (Are they the same thing? Not sure) and what-needs-what for a tree to bear olives. It turns out to be a little more ‘than girl olive tree and boy olive tree are married by the humble bees (sic) and they have olive babies‘. Below is an excerpt from Darwin’s Natural Selection where he describes when the importance of bees dawned on him (and thus humanity) and (he elaborates) that plants have male and female ‘bits’:

From Darwin’s Natural Selection. Bees doing marriage apparently because in Victorian times the idea of plants having sex (unmarried) was just a little too out there.
Marrying your cousin, however, wasn’t…Darwin.

Rules-for-getting-olives from Olive Trees

In a nutshell (mostly from here). Either;

  1. No olives: The tree is sterile, maybe the child of olive varieties (see quote below): Or;
  2. Abra-ca-dabra…olives (maybe): The olive tree is a self-pollinating variety. The maybe because it can be hitting or miss – a tree can go 5 years producing nothing. Or;
  3. The variety is not self-pollinating. Here lie a few hurdles, so maybe olives:
    • Bees don’t particularly like olive flowers, so it all rather depends on the wind, and;
    • Olive trees like to mix it up. It trees A and tree B are the same variety, you are not going to get olives. You need two different but compatible varieties. Of course, the question then is whether (a) the new offspring is a ‘new variety’ with hybrid olive fruit and (b) whether that hybrid can ‘breed’ with its siblings or parents. Closest I got to an answer below (though I did not look hard!):

When these varieties of olive trees do cross-pollinate you benefit with a  higher yield of 10% or more.  When olive trees cross-pollinate it does not change the fruit of the tree but it changes the seeds in the fruit of the tree which then grows to be a hybrid tree. Cuttings of your tree will be clones, seeds germinated from the fruit of the tree will then be hybrids but the hybrid tree may take 10- 15 years to fruit, if the seed is not sterile.    

Olive tree pollination and yields

Olives or Not?

The disappointing conclusion I reached, based on the above, was that the probability of our trees producing olives was pretty low :

  • We are in the middle of a city: trees are probably ‘ornamental’ (sterile?) and there are not groves of olive trees blanketing the Auckland hillsides, so the wind-pollination and the olive tree varieties’ swipe-left pickiness is not really going to help things.
  • Both trees flowered about the same time as I heard the podcast…but as my wife quite rightly pointed out: no olive stones knocking around anywhere.

But, guess what

A couple of weeks ago I was looking out the window (through) the tree at some beyond) when am an olive came into focus on one of the tree’s branches. Then I realised there were THOUSANDS of olives.

Project Olive was back on.

Just need an olive press now >>>