I visited an olive orchard here in Texas about five years ago(Not the one mentioned below), bought two small trees in a one gallon container and planted them immediately in the ground. They are unprotected and managed to survive so far. They are slow growers due to the nature of the soil perhaps and I didn't do anything for them so far except watch them grow very slowly. So far no sign of fruit and regardless whether I get fruit or not, these are beautiful trees in my yard.
There is a relatively new high density olive orchard not far from my house. They planted 23,000 trees on 33 acres in a location that is not known for olives. Their mix consists "of 17,000 Arbequina, 4,500 Koroneiki and 1,500 Arbosana trees." Arbequina their primary variety, does not need cross-pollination.
"Koroneiki: A Greek variety known for its anti-oxidant properties and light, fruity flavor. It produces small olives, but with greater yield. We are using Koroneiki trees as a cross-pollenator. The tree is of medium vigor with a spreading habit and an open canopy. The leaves are elliptic lanceolate; short and narrow. The fruit is small ovoid and slightly asymmetric. It ripens early and has high and constant yields with a very high content of oil. The Koroneiki variety is an early bearer which also flowers early and produces lots of pollen. They are often planted with Mastodies as a pollenizer.
- Arbequina: A Spanish variety that is prized for its high quality, buttery oil with a lightly peppered finish. It is a tree of medium vigor with a weeping shape. It has a crown of average size and produces a small amount of new wood each year. The leaves are elliptical lanceolate in shape and shiny dark green in color. The fruit is spherically symmetrical in shape, small in size (1.75 – 2.0 grams) with a rounded top. Fruit is black at maturation which occurs in mid season (the second half of November), but not all at once. The yield in oil is good (20 – 22%), of excellent quality with good organoleptic characteristics.
Arbosana: A Spanish variety that is small in stature with high yields. The yield in oil is very good (19-20%), and the oil has a unique fruity flavor. This variety is late maturing with high producing fruit with a tendency toward alternate bearing. Resistant to leaf drop and cold, this is a tree of lower vigor and high productivity leading to high density planting."
You can read about what they did here:
http://txolive.com/
Below are Photos of my two olive trees