Olive trees can be grown all over the world in areas where winter temperatures do not fall below freezing. In the United States, they can be grown in USDA growing zones 8-10. Olives can be used for many things, from delicious garnishes to an excellent, cold-pressed cooking oil. In the wild, the trees grow from seeds that are spread by birds and animals.
Modern growers often grow olive trees from cuttings because cuttings are essentially the material to clone identical trees from the original. This is especially useful when propagating hybridized olive trees.
Growing from Cuttings
Growing olive trees from cuttings is done in much the same way as growing any other tree from a cutting. First, select a healthy twig that is about the size of a pencil. Next, strip the leaves away from the lower 2/3 of the twig, then dip it in a rooting hormone mix. Finally, place the twig in dampened soil, and keep it watered. It will take two to three weeks for an olive branch to root and begin to develop.
Growing Olives from Seed
While wind, weather, birds and animals once spread olive seeds very handily, for humans to grow olives from seeds is a little more complex than just gathering the seed and tucking it into the ground.
First, you will need fresh olives that have not been processed in any way. The olives most people purchase at the supermarket have been cooked or pickled. This destroys the viability of the seeds, even if they have not been removed from the fruit.
It is recommended that you pick undamaged, ripe fruit from the tree. It should be selected while it is still a green color, not yet turned black.
Place the fruit in a bucket and cover with water. Bruise the fruits until the encasing shell is lightly broken, but not hard enough to break the pits. Soak overnight, stirring occasionally. In the morning, stir again, then pour the water off along with any “floaters.” The ones that float are probably rotten.
Clean all the fruit off the pits and nick the ends of each pit with a pair of clippers. Be careful not to nick too deep as this will ruin the seed. Soak the seeds again for 24 hours in room temperature water.
Prepare a cold frame to receive the seed pots. Place each seed in an individual growing pot filled with a half and half mix of sand and compost. Put the pots in the cold frame. Using a germination mat, keep the cold frame at about 60 degrees Fahrenheit for a month. This is warm enough to keep the seeds from freezing, but cold enough to act as a dormancy period. During this time, keep the top 2 inches of the pots moist by misting them, but allow the bottom half of the pot to dry out to prevent fungus problems.
During the second month, increase the temperature in the cold frame to 70 degrees F. During this time you should begin to see seedlings emerge. As they do, decrease the temperature of the propagation mat until the temperature inside the cold frame matches that of the outside air. Allow a few weeks to harden off the young plants as summer begins to wind down.
Transplant the young olive trees into the garden when the weather begins to cool so that they will not be challenged by the summer sun.
Can Olive Trees be Grown in Pots?
Yes, olive trees can be grown in pots. Simply transplant the young tree you have started from cuttings or from seed into a large clay or wooden pot. You will need to be judicious with watering it, not too much and not too little. It will need a fertilizer, as well. Olive trees will even bear fruit while growing in a container, but you might need to be careful to produce conditions that are nearly like the seasons around the Mediterranean Sea, and you will need more than one tree. Olive trees are usually pollinated by the wind, so you might need to position a fan near your blooming trees for the sake of pollination.
Lovely Ornamentals and Bonsai
Even if you don’t have any fruit on your potted olive tree, they make beautiful ornamental plants, and can even be coaxed into becoming bonsai. Growing small trees indoors helps clean the air in your home, and encourages that lovely, forest aroma that goes with growing things.
Better yet, if you are a pet owner, olive trees are a guilt-free houseplant. They are believed to the non-toxic to both dogs and cats. When compared to many attractive plants that can be fatal to your pets, this is excellent news for people who like both plants and animals.