Olives thrive in areas with long, warm growing seasons and moderately cold winters. When planted in areas that lack these conditions, the trees grow slowly and typically fail to produce fruit. However, olive trees make lovely ornamental plants, and many homeowners choose to plant the trees even when climate does not support fruit production. You should grow olive trees from cuttings to increase the beauty, health and fruit-bearing ability of the plant.
Avoid propagation by seed, as seed propagated olive trees tend to grow small and rarely resemble the parent trees. Instead, use stem cuttings to start your olive tree. Take a 12-inch long by 2-inch wide cutting from a mature tree, remove any leaves, treat the cutting with rooting hormone, plant it in a rooting medium and keep it lightly moist. Roots should begin to form within eight weeks.
Transplant your olive tree to a wide container filled with soil to encourage root growth. Olive trees do not require deep containers, as their root system is shallow. You can add compost to the soil to increase the nitrogen content. Do not transplant your live tree to a container until at least 10 weeks of age.
Plant the olive tree in full sun on well-drained soil when the root system is developed and the trunk is strong enough to support the weight of the tree. In colder climates, raise the soil around the trunk of the tree to a height of 12 to 18 inches during the winter months. This will help protect the olive tree from the cold temperature.
Water the tree deeply approximately once per month. Olive trees can survive drought conditions for long periods, but regular watering will ensure the plant remains healthy and will increase the likelihood that the tree will bear fruit. Over-watering young trees may lead to root rot or fungal infections.
Fertilize the olive tree with 1 to 2 pounds of nitrogen fertilizer each year. Fertilize in December to encourage fruit bud formation. When necessary, you can fertilize again during the early spring, as soon as new growth appears on the tree.
Prune the olive tree during late spring to shape it and to regulate fruit production. Olive trees bear fruit on the previous year's growth. Remove low branches and suckers each year, and thin out dead or diseased wood.
Watch for signs of fungal or bacterial infections in the olive tree, and treat the tree for any insects or parasites as soon as possible. One bacterial disease that affects olive trees, called olive knot, primarily spreads via infected tools. To prevent infection with olive knot, clean your tools frequently and avoid cutting or pruning healthy trees with the same tools used on diseased trees.