Does anyone know of a site that maps out the areas in the U.S. where olive trees can be grown?
Thanks.
I can’t find a map or any mention of olive culture in NC but the following from “Growing Olives in Texas Gardens” by George Ray McEachern and Larry A. Stein, Extension Horticulturists at Texas A & M University, found at
http://aggie-horticulture.tamu.edu/extension/fruit/olive/olive.html
makes me doubt that you could grow olives anywhere in NC. (Olives like mediterranean climates, warm and relatively dry so that nights are cool but with little frost. NC along the coast is too humid in the summer and the piedmont and mountains are too cold in the winter.)
"Climate is the most important limiting factor in the distribution of the olive in Texas and elsewhere. Temperature controls growth, reproduction, and survival of the olive. Growth begins after mean temperatures warm to 70 degrees F in the spring and continues until temperatures drop below this point in the fall. Unlike the fruit trees that we are familiar with, such as the peach, the olive does not set fruiting buds in the fall. Instead, the olive will only set flower buds after being exposed to cool night and warm day temperatures during the winter. This unique warm day/cool night vernalization is essential for fruit bud development.
The olive must experience vernalization to produce fruit; however, it will freeze from extreme cold. Although the olive is the most cold-hardy of the subtropical fruit trees, it will sustain damage to leaves and small stems at 17 degrees F and more severe damage at 12 degrees F. The tree can be killed to the ground with temperatures below 10 degrees F. Mature trees can regrow from underground parts following a severe freeze."
Absolutely Wekks. Check this site and if you look around long enough you should find everything you need. I experimented with it in my year round green house. I live in New Enlgand and I got two seasons with varied results. I gave it up for more than one reason…the biggest reason was my kids. They needed my time more.
If it is warm enough to grow citrus where you are, then olive trees should survive, but as Yeah points out, they need a cool(ish) period to thrive.
USDA Plant Hardiness Zone Map: http://www.usna.usda.gov/Hardzone/ushzmap.html
Olives would like Zone 8 or 9 I’m guessing.
More detail here: http://plantsdatabase.com/go/2374/
I live where olive trees do very well. They’re nice to look at, but they make a mess. Don’t place one where you will be walking or sitting.
Don’t they take forever to grow and twice that to yield olives?
When I was a kid in San Diego (a Mediterranean climate), we had an olive tree in our front yard and a lemon tree in the back. While I often grabbed a lemon to put on my fish sticks, the only thing a young boy could do with the olives was to puncture their dark skins and throw them at his friends – who would return in kind. There were many, many olives produced by this tree, and they tended to end up on the sidewalk where they would stain the concrete.
So let’s suppose I still leved there and the tree was still there (I think it’s been cut down, but I haven’t looked). What could I do with the olives? Make olive oil? How? Pickle them? How?
I saw a TV show that said you need to soak the olives in salt water for a while (a few weeks i think) before you could eat them. Something about bitter alkaloids making them taste nasty.
Weeks , I work in a nursery geared to plants native to the Southeast, and volunteer at the NC Botanical Garden Chapel Hill. I’ve never heard of anyone successfully growing olives here, or on the coast. I wish it were true, as I’m an olive fanatic. I have a shift at the NCBG this weekend, and will try to get a good answer for you from the curator.
Sounds like it’d be easier to move to Italy. 
If ya can’t wait a few days, or would like to have a direct talk, call the NCBG, http://www.unc.edu/depts/ncbg/ This is the slow season, plantwise, and the folks there are wonderful and accomodating about questions. They’ll give you all kinds of good info. 
I’m gonna bring up the question this weekend anyway, though, cause I wanna know, too!
elelle, Thanks. I would love to hear what they say at the NCBG! What a great link.
Wilmington, being a zone 8 (Hotter than Hell in in the summer but Really freakin’ cold at the moment) appears to be a parting contestant.
Ask, if you would, about cork trees while you’re at it. If I cant grow olives maybe I can grow a few corks!
OOOHH. Hey, ask them if I can raise truffles ( the fungus) on my land!
Awaiting your reply,and dreaming of my next visit to A Southern Season,
Weeks
Here’s what the California Rare Fruit Grower’s site has to say on the topic:
*The olive requires a long, hot growing season to properly ripen the fruit, no late spring frosts to kill the blossoms and sufficient winter chill to insure fruit set. Home grown olives generally fruit satisfactorily in the warmer coastal valleys of California. Virtually all U.S. commercial olive production is concentrated in California’s Central Valley, with a small pocket of olive acreage outside Phoenix. The tree may be grown as an ornamental where winter temperatures do not drop below 12° F. Green fruit is damaged at about 28°, but ripe fruit will withstand somewhat lower temperatures. Hot, dry winds may be harmful during the period when the flowers are open and the young fruits are setting. The trees survive and fruit well even with considerable neglect. Olives can also be grown in a large container, and has even appeared in shows as a bonsai. *
So if your winters drop below probably 26 degrees Farenheit, you’ll lose the crop of fruit, which makes the tree bad any place with winters colder than that, if the trees are intended for fruit production. While you can grow them in containers, they are a bitch to move back and forth just to have olives.
Further processing of fruits is necessary because if you’ve ever tasted a raw olive, it’s almost a painful experience (tried it once, never again). There are a few varieties with fruit low enough in the offending alkaloid that they can be eaten after being sun dried, but most require the brine, or LYE (yes, lye) treatment:
*Olive fruits that are to be processed as green olives are picked while they are still green but have reached full size. They can also be picked for processing at any later stage up through full ripeness. Ripe olives bruise easily and should be handled with care. Mold is also a problem for the fruit between picking and curing. There are several classical ways of curing olives. A common method is the lye-cure process in which green or near-ripe olives are soaked in a series of lye solutions for a period of time to remove the bitter principle and then transferred to water and finally a mild saline solution. Other processing methods include water curing, salt curing and Greek-style curing. Explicit directions for various curing and marinating methods can be found in several publications including Maggie Blyth Klein’s book, Feast of the Olives, and the University of California Agricultural Sciences Publications Leaflet 21131. Both green-cured and ripe-cured olives are popular as a relish or snack. For California canned commercial olives, black olives are identical to green olives. The black color is obtained by exposure to air after lye extraction and has nothing to do with ripeness. Home production of olive oil is not recommended. The equipment required and the sheer mass of fruit needed are beyond most households. *
Note that even if you don’t plan to make olives, just to make olive oil is not worth it. You need a LOT of fruit to get any appreciable amount of oil out of them.
The cultivar seen in the missions of California is “Mission”, which is typical in California.
Cutting grown trees usually start producing in 4 years, but the variety “Rubra” ( a French Olive) is precocious and begins producing in 2 years. It’s very productive and while the fruit can be used for pickling, most of the fruit is used for oil.
However, the trees are very lovely in and of themselves. Nice gray green foliage and knobby twisted trunks. They are common in California gardens, but if your winters aren’t too cold (not below 12F), they make lovely additions to the garden. They also live for 500 years, and while they usually get to 50 feet high, pruning can keep them at 20 (and this is the height commercial producers keep them). There are also fruitless varieties specifically for ornamental value.