Olive trees are some of the oldest fruit trees known to man. Olive trees are mentioned in connection to the biblical flood and are incorporated into most of the religions of the Mediterranean where the tree grows. Some olive trees that are alive in the Mediterranean region are thought to be more than 2,000 years old. Because olives thrive near in warmer weather such as that found near the equator, they cannot survive the cold winter in most of the United States. But olives will survive in parts of southern Florida and Texas as well as California. Outside of these areas, an olive tree must be grown in a container.
Determine your temperate zone by consulting a USDA plant hardiness map. Olives will grow in USDA hardiness zone 9, where temperatures do not fall below 20 degrees Fahrenheit. Olive trees will sustain damage at 17 degrees and will die if exposed to temperatures below 12 degrees. If you do not live inside zone 9, plan to plant your tree in a container.
Select a location for your olive tree that is in full sun and has well-draining soil. Olives will thrive in soil of any quality and most pH ranges, but must have well-drained soil to prevent root rot.
Propagate olive trees from hardwood cuttings by taking a cutting from the tree’s limbs. Wait until late fall, winter or early spring while the tree is still dormant. Take a cutting early in the morning while the tree is swollen with water. Select an olive tree that is healthy and disease free. Snip 6 inches of stem away from the tip of a limb. There should be at least three places where foliage emerges from the stem (leaf nodes) on your cutting.
Strip off the lower two-thirds of foliage and place in a sandwich bag with 2 tbsp. of water to keep the limb alive.
Fill a 6-inch pot with peat moss and wet it until it is the consistency of a wrung-out sponge. Dip the lower end of the cutting in rooting hormone. Insert the cutting in the container two-thirds of the way and cover with a plastic sandwich bag.
Place your cutting in a sunny windowsill out of direct sunlight. Check the cutting daily and water from the bottom any time the soil appears to be drying out. Roots should emerge within 45 days. Remove the sandwich bag whenever roots emerge.
Repot container olive trees when the tree becomes rootbound. Never give the tree a container that is more than 2 inches larger than the root ball. This will prevent the plant from sitting in wet soil and developing root rot. Bring containers in during the winter to prevent them from freezing.
Amend soil that is heavy in clay, such as the kind found in southern Texas with gypsum before planting by breaking up the soil with a rototiller and spreading gypsum over the surface. Turn gypsum into the soil with the rototiller. The sand-filled soil of southern Florida will probably need no amendments for growing olives.
Plant a tree in the ground by digging a hole that is twice as large as the plant, but no deeper. Place the plant in the hole and cover with dirt. In winter, mulch heavily around the tree to protect it from freezing.