Make my Olive Trees Fruitful !

October 7, 2009 4:17 PM

How can you encourage an Olive tree to fruit ?

What can I do to encourage my previously barren Olive trees to produce fruit ?

I have an Olive tree in my garden. It's 7 years old and we have yet to see any olives.

I live in Wellington, New Zealand and the climate looks like this. (the seasons are back to front if you're a Northern Hemisphere person and so we're currently heading into Spring).

I know that some Olive trees require the company of others to pollinate but my neighbours have three and six Olive trees respectively and they don't get any fruit either. I'd really like to help all three houses produce some olives !

I also know that there are Olive trees in Wellington which produce Olives - these for instance - which are reasonably close to where I live - so it's not completely impossible.

I would love to hear from someone who knows how I could encourage the tree to produce fruit.

(I expect someone's going to ask me what variety of olive tree it is and I don't know that - would a photograph help ?)

posted by southof40 to home & garden (7 comments total)

Don't prune heavily, fruit sets the second year after branches grow.

Make sure it's getting the required minimum cold temperature during the winter.

Shield or somehow ensure the blossoms aren't being blown off or washed off in heavy rain.

It's not unusual for olive trees to randomly stop bearing fruit for years at a time.

Have you tried the Google? I learned all that in 23 seconds.
posted by torquemaniac at 5:17 PM on October 7

You're going to need a pollen source for your tree, of course. Namely, another olive tree in the same general location, close enough for pollination to occur, via either the wind or some kind of animal, like a bird or bee.
posted by Cool Papa Bell at 5:28 PM on October 7

Oh, on preview, you covered that. Sorry.
posted by Cool Papa Bell at 5:29 PM on October 7

Doesn't need an Oliver tree? How nearby is nearby?

Guess not.

http://www.crfg.org/pubs/ff/olive.html

Maybe you need to get out there with a bit of a feather duster to spread the pollen about. And ditto on the "cold enough" - I've heard that in more temperate climates you can put ice on the tree in the winter (roots) to force it dormant (YMMV, Do Your Research First).
posted by tilde at 6:26 PM on October 7

There's some cultivars of olives which do not ever fruit, are you certain your tree is not one of them?

Another possibility is your neighbor's trees are being intentionally sprayed to prevent them setting fruit (many people, especially people who have olive trees planted next to patios, find the ripe fruit a bug not a feature). If your neighbors fall into this camp, your olive tree might not have the handy cross pollinators you thought (also, some species of olives are self-fertile but cross pollination usually makes for better fruit yields).
posted by jamaro at 6:32 PM on October 7

Thanks for all the answers (any more are welcome)

@torquematic - I did try Google but you're obviously better at it than I am. Did you have a reference for what you quoted ? I was also trying to find practical experience of someone who lived in a similar climate to mine (which I consider, perhaps incorrectly, marginal for olives). I'm interested in the fact that a minimum temperature is needed did you see what that was ?

@cool Papa Bell - thanks I wasn't sure whether some varieties could pollinate themselves ? (That may be an incredibly stupid thing to think - my knowledge of plants is not deep). I take it that it would need to be the same variety ? Or is there some latitude ?

@tilde - the other olive trees are : group of six - 10 metres in the same direction as the predominant wind (ie pollen would have to make it back against predominant wind); group of five (I said, incorrectly, three before) - also 10 metres perpendicular to the predominant wind (ie pollen would have to make it across wind). Should perhaps explain that Wellington is a pretty breezy place ! I've heard of hand-pollination - is that something that could be done by an amateur to significantly improve outcomes ?

@jamaro - I didn't know that about the 'no-fruit' varieties. I have a dim recollection from the tag which was on the tree that fruit was at least a possibility though. WRT spraying no I've spoken to both sets of neighbours and both would like some olives ... I suppose it's possible that they are unintentionally spraying them in a way that would stop fruit setting ? They're both significantly more 'gardenery' type people than me and undoubtedly do some spraying (I'm more a laissez-faire type unless there's something edible that might come out of it !).
posted by southof40 at 7:53 PM on October 7

I Googled "Olive Tree Pollination" and found that info on this page.

Olive trees are mainly wind pollinated, so if the wind doesn't ever blow from your neighbor's direction(s) you may have to manually pollinate.

Aside from that, I recommend you determine which variety (cultivar) of olive tree you own and determine if it's recommended for your growing zone. If you have an agricultural extension there (we have county master gardeners here - I'm one) they'll be able to help you make the determination and tell you what growing zone you are in. They'll likely be able to answer many of the other questions you have - such as the minimum winter temperature. If this doesn't work or isn't applicable to you, then go to the library/bookstore/garden center and find a book to help you get this information. You might also want to ask your neighbors if they know more about both their & your trees.

You'll probably find that you're slightly in the wrong zone, close enough to grow the tree but far enough away that it won't successfully bear fruit. I have this problem with mangoes, I live a couple hundred miles or so north of the recommended growing zone which - much to my dismay - disallows me from successfully producing them. Good luck!
posted by torquemaniac at 9:27 PM on October 7