The olive is an extremely long-lived tree in the Mediterranean. Some trees that still bear fruit today are thought to be over 2,000 years old. Although the olive tree may be propagated from seed, many olives grown today are hybrid plants. The seed olive, when grown, will not resemble the parent plant. Instead, many olive growers choose to grow olives by rooting cuttings. The tree will grow in USDA hardiness zones 9 or warmer. These are parts of the United States in which winter temperatures never drop below 20 degrees Fahrenheit. These regions include southern Texas, Florida, Arizona, Nevada, Louisiana and California as well as Hawaii.
Time your olive cutting for August or September. According to Texas A&M, this is when you will achieve the best results from your cuttings.
Select a healthy, disease-free branch that is as thick as a pencil. Position your pruning shears 8 inches from the end of the branch, below the point where a leaf emerges, and cut cleanly through the branch.
Mix a potting soil made from one part peat moss, one part sand and one part vermiculite. Fill a 4-inch-wide container with the potting soil. Water until the soil is as damp as a wrung-out sponge.
Strip off the leaves from the lower two-thirds of the branch, and dip the cut end into rooting hormone. Insert the cutting halfway into the potting soil.
Place a plastic freezer bag over the container and tree cutting. Place the container in a sunny windowsill and check daily. Water the container any time the soil seems dry. Remove the bag in six to eight weeks once roots sprout from the tree.
Water the tree seedling with a liquid, balanced fertilizer diluted to half-strength.
Transplant the seedling into the ground in spring in zone 9 or warmer. Leave your olive in a container and move it indoors during winter months in cooler climates. Olive trees will freeze and die if temperatures drop below 12 degrees.