Frequently Asked Questions

As far as sub-tropicals are concerned, they are reasonably common in the Pacific Northwest, growing in the ground as far north as coastal British Columbia in USDA zones 8 and 9.  They are also grown in pots or as Bonsai in any climate zone:

 

#1  Do olive trees really grow in Oregon?

Well, we feel our site Oregon Olive Trees is the best site out there!  Or feel free to email me your questions directly.  I am also have free “open field” days in the fall where interested parties can come and see what we are doing.  And I do show the groves and answer questions for people interested in buying olive trees, on appointment.

#3  Where can I find out more about growing olive trees in Oregon?

The first thing you should do is plant at least 200 olive trees.  It takes a lot of olives to make olive oil; and making extra virgin oil probably also requires a expensive press or mill.  As of right now, I am not aware of any public mill in the Pacific Northwest, although they may be coming soon (I am aware of at least two families who have planted thousands of trees within 25 miles of us).

That said, olive oil has been made for thousands of years, under what we now would consider primitive conditions.  The University of California Publication 2789 describes the simplest process.  Also, there is a [relatively] inexpensive press available:

http://www.oliveoilsource.com/pressesmodel5.htm

 

Look for information from the regions where olives are commercially grown and the climate is most similar to ours: coastal northern California, Tuscany (Italy), France, South Island New Zealand and Tasmania.

Here are some magazine articles that may be of interest:

http://oregonwinepress.com/article?articleTitle=vine+to+branch--1288373993--567&ref=RlJPTXtBcnRpY2xlOkNhdGVnb3J5UG9zdEJyb3dzZXJ9VE97QXJ0aWNsZTpDYXRlZ29yeVZpZXdlcn1NRVNTQUdFe2FydGljbGVDYXRlZ29yeT13aW5lX25ld3N9

http://www.capitalpress.com/content/jm-olive-trees-w-art

http://ethosmagonline.com/archives/16510

Oregon Farm Produces Quality EVOO

 

Here is some olive growing information available on the web, based on California conditions:

http://cesonoma.ucdavis.edu/SpecialtyCrops/Olives.htm

http://rics.ucdavis.edu/fnric2/crops/olive.shtml

http://cetulare.ucdavis.edu/newsletterfiles/newsletter715.htm

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

http://www.davero.com/trees.php

http://www.mcevoyranch.com/html/images/OliveTreeBrochure.pdf

http://www.santacruzolive.com/planting.asp?page=variety

http://www.groworganic.com/pdf/lit/Olives-L.pdf

http://www.olivinursery.com/pages/basic_farming_info.html

http://www.sierragoldtrees.com/varieties/olives.htm

http://www.burchellnursery.com/sections/fruit_trees/olives

http://www.novavine.com/plant_materials/olive_trees/varieties_characteristics.asp

http://www.nurstech.com/highdensity.html

http://www.oliveoilsource.com/index.asp

http://www.whfoods.com/genpage.php?tname=foodspice&dbid=46

Just remember: Oregon is not California…

Here is a book list:

"Olive Production Manual" (the first book I bought on olives; mostly about table olives)

"Organic Olive Production Manual" (sister to the book above; mostly about olive oil olives)

"Pruning and Training Systems for Modern Olive Growing"

"Producing Table Olives" (best book for making table olives)

“Table Olives” (for academics)

"Olive Propagation Manual"

“World Olive Encyclopedia" (very inclusive, expensive)

"World Catalog of Olive Varieties" (expensive “coffee table” book with nice pictures of olives)

"Oregon Viticulture"  (lots of commonality of farming with grapes)

"Cover Cropping in Vineyards"  (ditto comment above)

"The Olive in California" (historical, mostly)

"Olives: The Life and Lore of a Noble Fruit" (a journalist’s review of the olive world)

"The Angel Tree" (a good story - not sure how much is true though!)

“The Olive, Tree of Civilization” (nice “small format” coffee table book)

“Olive Oil” (by Charles Quest-Ritson; excellent little book about districts of production and olive oil)

“Olives” (by Ioannis Therios; good but could be better: lots of outlines and a little short on facts)

#4  What other resources do you know of, for growing olive trees, that might relate to Oregon?

#8  I want to make my own extra virgin olive oil!  Where can I find out more?

A much more reasonable proposition!  This University of California publication should get you off to an excellent start:

                                       Olives: Safe Methods for Home Picking

#10  I want to make my own table olives!  Where can I find out more?

Well, you don’t, of course; that’s just what we recommend if you want to grow and make your own extra virgin olive oil at some reasonable volume / price point.

The cheapest olive mill to make your own extra virgin olive oil will probably cost you at least $20,000, used.  This is for a very small mill, say 50 kilograms an hour capacity.  To justify this kind of investment, my own personal feeling is that at least 200 trees are needed.  Some other options, if you are willing to let others make your olive oil:

 - Custom Milling is the term used when other people make olive oil from your olives.  This in general requires a substantial minimum amount of olives; typically in the range of 800 pounds to one ton.  The cost for this service seems to run around $400 minimum, in California, at this time (2008).

 - mills with “Community Milling Days” will accept much smaller amounts, sometimes there is no minimum quantity, but they combine your olives with all others that come in the same day to create a “press run”.  When you come back to collect your oil, what you get is your share of a blend of everybody's olive oil.  So much for all that loving care you lavished on your special olives!  The cost for this service in California seems to be currently around $1.00 for each pound of olives, which means the milling charge alone might be somewhere in the range of $15 - $20 for the result of a liter of “blended” extra virgin olive oil.

If you want to make your own olive press, the physics of it are pretty simple.  As a minimalist you might be able to make olive oil with a setup based on: something like a garbage disposal to grind the olives; a device like an ice cream churn to maxalate the paste; and maybe a car jack based press with some woven straw placemats to squeeze the oil (and water) out; and a two gallon pail to allow the olive oil to separate.  I can pretty much guarantee you can’t make an extra virgin quality product this way.

 

#9  Why do I need to plant 200 trees to make my own extra virgin olive oil?

Oregon Olives 

Think global - buy local.

We are located in the Eola Hills, near Amity Oregon.  This is south-west of Portland, and north-west of the state capital, Salem.

#2  Where did you say you are located?

Oregon Olives

Oregon Olive Oil

Oregon Olive Trees

My wife and I bought five acres in Oregon in 2004 - and I resolved to make the land productive and fruitful.  The land had previously been planted in plums (the then owner said they didn’t do any good), then cherries (they did even worse) and then back to plums (doing even worse than the first time!), and then the trees were ripped out and the land was left fallow.  When asked what the problem was, the previous owner said:

- too dry (the land being dry farmed), the soil being too thin to store a lot of water to get the trees through the definite Mediterranean-like summers;

- too hot - the land has a southern slope; all his other cherries and plums on this hill were on the northern slope.  (N.B. I think this is really just the water issue again: the southern slope made the water problem all that much worse.  Although it is interesting to see heat waves shimmer across the newly plowed land when the temperature is “only supposed to be” 65 F or so…)

In the long past most of this hill was planted in cherries (north slopes) and filberts (south and east slopes); more recently pinot noir wine grapes (south, east  and west slopes) and Christmas trees (north slopes).  The filbert plantings are all coming out, due to Eastern Filbert Blight.  The Christmas tree market is glutted, and production is being phased out on the hill.  When I talked to some grape people, they were hesitant, because of:

- thin rocky poor soil.  Grapes make good wine when they have to struggle, but there is a limit!

- there is a glut of new wine grape plantings; it might not be a good idea for a small holding to plant at this time.

And grapes need a lot of chemical spraying here, something I don’t like to do.  Watering is also a problem, the land is in a restricted area for ground water rights (in a place where we get 32 - 40” of rain a year, I didn’t expect water to be such a problem!).  I had thought about growing vegetables (I do still grow a fair amount of garlic, but the land is really too sloped for row crops). 

So, what to do?  Hot, dry, sunny, rocky hillside land…  exactly the sort of land that in Mediterranean Europe is used to grow olive trees! 

And so the adventure began...

#11  I’m curious - why did you decide to grow olives in Oregon?

#6  I want to grow olive trees in North Carolina/New York/Idaho/Utah/[some other place less than USDA zone 8A]!  Tell me how to do it!

This is probably the most common question I get now-a-days.  Yes, you can grow olive trees in these places!  Just probably not the way you had envisioned it.

Olive trees are not adapted to climates less than USDA zone 8.  Let me say that again, longer: the genetic variance in the olive tree genome does not support long term viable growing for productive purposes in places where winters with some regularity get colder than 10 F (-12 C) for any length of time.  In fact, they aren't really well adapted to zone 8A.

So, the trick is obvious for those of you in these places: you must modify the micro-climate around the olive tree to be USDA zone 8B or better (that would be > 15 F, or about -9 C).  Examples:

- plant the olive tree in a winter heated greenhouse or similar enclosure.

- plant the olive tree in a pot, and move it into a warmer place when cold weather moves through.

Several people I know in New York are doing both: they have the olive trees in pots, and move them from outdoors into a greenhouse in winter.

If you live in USDA zone 8A, you might be able to get away with just a microclimate you already have, or slightly modified for olive trees.  I keep citrus and even avocados outdoors for most of a normal winter (and all of a "warmer one", like this one) by planting them in pots and moving them under a patio overhang and next to a sliding glass door in the winter.  This works fairly well until it gets colder than 28 F or so (remembering that avocados and some citrus are very sensitive to any freezing temperatures); and I can also throw some protection over the plants to protect down to about 25 F:

You can read the whole story about these citrus and avocado trees during the winter of 2011/2012:

Avocados in Amity Oregon

#7  I want to grow olive trees in pots.  When do I need to repot them?  What do I do in winter?  What cultivars might be best for pots?

If you keep the trees in pots, we recommend you repot them to a bigger pot size as soon as is convenient.  We repot AB46 size trees into a #2 round pots.

If you keep the trees in pots, we recommend you move them to shelter when the temperature falls below 25 F or so.  If you do this, you can have any cultivar you want, since cold sensitivity becomes a non-issue.

If you want fruit, for two trees we would recommend one of them be Pendolino, for pollination.  If you buy three trees, we would recommend three different cultivars for cross pollination.  Pendolino has a weeping form that some people really like, is moderately productive at a young age with medium size fruit that ripen first of all the cultivars we have.

Kalamata is a good choice for a pot, David thinks Kalamata is one of the prettiest olive trees with very large deep green leaves with a silvery underside that shimmers in a breeze.  However it is not very prolific fruiting at a young age.

Amfissa is another pretty tree with big shimmery green / silver leaves.  Also not prolific when young.

Arbequina is probably the most common tree used in a pot (if only because it is the most commonly available), it will have prolific amounts of small fruit.

Nocellara del Belice is another pretty tree with large dark green leaves that bears a large amount of large fruit at a young age, and is Carmen's favorite olive tree.  Probably needs more regular fertilization than others (needs "active farming" as they say, when grown in groves).

#5  I just bought some of your olive trees.  What do I do now?!

Our rule of thumb is: sell, plant or repot our nursery olive trees yearly. 

We plant trees on our own land in either April - May or September; Spring being the best time to plant, and early Fall the second best.  Planting is simple: just dig a hole, put the olive tree in the hole a little higher than it was in the pot, backfill with soil, and water.  If this is too brief of instructions, see:

                                       Oregon Olive Trees - Planting

                                       Planting Olive Trees

                                       Planting an Olive Tree

 

We repot trees  in the spring, April - May.  Typically, you want to double or triple the nominal size of the container to achieve maximum growth of the trees.  Our repotting sequence is:

AB46 -> #2 -> #5 -> #15 pots

We use a bulk potting soil, nothing special, any good commercial potting soil should work fine (however, avoid the ones with "special water storing crystals" or similar.  Olives don't like soggy roots).

We try to fertilize potted plants at about half the recommended rate every month (see directions for your specific fertilizer)

David@OregonOlivesTrees.com

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