The term “fruitless” can be a bit of an overstatement and some homeowners are unpleasantly surprised when they see a handful of tiny olives forming on the branches. Best planted in the spring or fall, the slow-growing fruitless olive trees will bloom each spring with clusters of yellowish-white, tubular flowers. The flowers themselves are sterile, so few if any fruits are produced, but you may get some small (non-viable) olives that develop from time to time. However, they are minimal and you will not notice them when they have fallen from the tree. Fruitless olive trees offer a big advantage if you live in an area of the country where fruiting olive trees are banned, either because of the widespread mess created by the falling fruits or the allergy-triggering pollen. The fallen olive fruits will stain driveways, paved areas, and decks, clog drains, and attract unwanted animals as they decompose. Fruitless olive trees spare you from all of these problems, while still maintaining the beauty and Mediterranean flair of true olive trees. Once your fruitless olive is established, it requires very little care. They are extremely drought tolerant and prone to a few problems or pests. The trees can produce suckers and may need to be pruned annually to keep their shape.
Light
All types of olive trees require full sun for healthy, prosperous growth. A good goal is to plant your olive tree in a place that gets at least eight hours of sunight a day. Keep in mind that those requirements will need to be maintained as the tree gets larger, too, so be wary of nearby houses or other large trees.
Soil
While fruitless olive trees can handle a variety of different soil conditions, it’s imperative that whatever mixture you choose has excellent drainage. For best success, plant your tree in a soil blend that is rocky or sandy (this can include mixing potting soil with perlite or gravel).
Water
Although fruitless olive trees are very drought tolerant, they should be given some supplemental water as they are first becoming established, and a bit during extreme heat and dry periods. Water your tree at its base and roots so you don’t damage its delicate leaves. Browning leaves and loss of leaves is usually caused by either insufficient water or waterlogged soil. Be sure to provide good drainage if you’re growing your tree in a container—a clay or terracotta pot will also help aid in drainage.
Temperature and Humidity
Fruitless olive trees can handle a range of temperatures, from desert heat to a bit of cold, and can tolerate some short-term frost. They are generally hardy down to 15 degrees Fahrenheit, though they should not be kept at that temperature for very long at all. Generally, they do best with a hot, dry summer and mild winter.
Fertilizer
While your fruitless olive tree is young, an annual application of high-nitrogen fertilizer in spring will encourage new healthy growth.
Fruitless Olive Tree Varieties
There are a few different varietals of fruitless olive trees available on the market. While they all closely resemble traditional olive trees, they vary slightly in appearance and fruiting. They include:
‘Majestic Beauty’: This varietal is the most reliably non-fruiting.‘Swan Hill’: This varietal rarely produces fruits and is also pollen-free as a bonus.‘Wilsonii’: These are beautiful, hardy trees, but they may in fact produce enough fruit to be noticeable.‘Little Ollie’ and ‘Skylark Dwarf’: Two compact varieties that are good for patios and containers.
Pruning Fruitless Olive Trees
If you’d like to try and prevent your fruitless olive tree from producing any olives at all, you can do some light pruning of the newer growth branches. Typically, these are the branches with flowers that will turn into olives. Keep in mind, you don’t want to go overboard with the pruning and destroy the shape of the tree. Another option when it comes to preventing fruiting is applying a fruit-inhibiting spray containing ethylene. Spraying needs to be timed to when the flowers are forming and is costly to apply every year, especially as the tree grows larger, so most people don’t find this to be a very practical option.
Common Pests and Diseases
There are several issues you may have to deal with when growing a fruitless olive tree. The branch and twig borer, a type of beetle, will bore holes into the olive tree to lay its eggs. The newly-hatched borers will burrow even further into the tree and can eventually kill the twig or branch they are in. The American plum borer, which is a type of moth, can cause similar damage. Prune out any twigs or branches with visible holes to prevent further damage. Additionally, several fungal diseases can affect fruitless olive trees. Good air circulation and plenty of sunshine will help prevent these diseases. If you suspect your tree is suffering from a fungal disease, it is best to take a sample to your local cooperative extension or a good nursery and ask them which disease it is and what is the best way of treating it.
