Most olive trees are evergreens that need warm temperatures, full sun and low humidity to thrive. These requirements leave growing zones 7 through 11 as ideal areas to grow olive trees outdoors. According to the University of California's Agriculture and Natural Resources department, olive trees can reach 25 to 30 feet tall and non-fruiting dwarf trees top out at 12 feet. With numerous varieties to choose from, olive trees are available to fit many zones, especially when grown in containers.
Grow Outdoors in Zones 7 Through 10
Olive trees have been around since 2,500 B.C., and hundreds of varieties have been cultivated for different purposes, typically for oils or food. Over time, olive trees have adapted on their own or been bred for diverse climates. The Arbequina olive is one type that is hardy outside down to zone 7. Arbequina trees resist frost and climate swings well. The black fruit will ripen in the middle of autumn.
Grow Outdoors in Zones 8 Through 10
Mission olive trees were named because Franciscan priests planted them at each new mission they opened. Cold hardy to 8 degrees, the olives are harvested October through November. Mission trees can grow 30 feet tall. Barouni green olives are commonly used for home pickling. They also are cool-weather tolerant. Lucca bears copious olives that are usually used to make olive oil.
Grow Outdoors in Zones 9 Through 10
All olive trees bear green fruit that ripens to black or brown. Some varieties are harvested green for certain uses and others are allowed to fully ripen before picking. Frantoio trees are grown for their oval, black olives that ripen in the middle of the season. Frantoio requires hotter climates to survive. Frantoio olive trees can achieve 26 feet in height.
Container Suited Olive Trees
Olive trees can handle a lot of neglect, so they are a perfect indoor plant to start with for anyone new to growing trees. Picholine olives can be picked green or black. They grow like a weeping willow does and take frequent pruning well; this comes in handy for low ceilings. An Arbequina's fruit are picked while still green and the tree grows vertically. Plant trees in pots at least 24 by 24 inches with high nitrogen and time-released fertilizer in well-drained soil. Bring trees inside during the winter in zones 7 or lower.