By Richard Flowers, ACCNP-Green Thumb Nursery-Ventura
With age, they pose a characteristic gnarled trunk with knots and wrinkles and are noted for their lacy, graceful, billowing, and picturesque form. They are know as one of the oldest cultivated trees in history that dates back to more than 2,500 B.C. These plants are called Fruiting Olives and may have been first cultivated in two places: Crete and Syria. From Crete and Syria Olives spread to Greece, Rome and other parts of the Mediterranean area. Olives are also grown commercially in California’s Central Valley, Australia and South Africa. There is some disagreement over when the trees first appeared in California. Some say they were introduced in 1769 when seeds brought from Mexico were planted. Others say the date 1785 when trees were brought in, to make Olive oil.
The Olive is botanically called Olea europaea, meaning European Olive. Olives are related to such plants as the Ash, Jasmine, and Lilacs. There are hundreds of cultivars that are assigned to the name Fruiting Olive. Several will be detailed below. Olives are an evergreen or technically an ever-gray tree that has the ability to grow 50 feet tall and 30 feet wide and can live for nearly 500 years. If for any reason they are cut down down to the ground, the tenacious stems will grow back. Oftentimes, they are kept smaller
than the designated height by pruning so they are not so overpowering and more manageable to smaller landscapes. Fruiting Olives produce small pollen-rich white flowers in spring. For those of you who are allergy sufferers, you may need to shy away from this plant unless you elect to use fruitless Olives instead, however this article is focused on Fruiting Olives.
They are known to withstand considerable neglect but to be able to grow Fruiting Olives successfully, they require a long, hot growing season to properly ripen the fruit with no late spring frosts to kill the blossoms and sufficient winter chill to insure fruit set. Fruiting Olives love the full sun and are drought tolerant once established. They are at home in and our own Mediterranean climate of which they are native to (they are also native to Tropical and Central Asia and various parts of Africa) and are hardy to temperatures as low as 15 degree F without damage but older trees may get some tip damage. Green fruit is damaged at about 28°degrees F, but ripe fruit will withstand somewhat lower temperatures. Conversely, average winter temperatures above 50°F will inhibit fruiting.
Fruiting Olives thrive in a wide variety of soils as long as it is well-drained. Home grown Olives generally fruit satisfactorily in the warmer coastal valleys of California. Care should be exercised not to expose your Fruiting Olive to hot, dry winds which may be harmful during the period when the flowers are open and the young fruits are setting. Do not be alarmed if leaf drop occurs because leaves are replaced every two or three years and this phenomenon usually coincides at the same time new growth appears in the
spring. Strong winds will “sculpt” (grow in the direction of prevailing wind) the trees, but otherwise they are quite wind-tolerant. A monthly deep watering is recommended on established trees is normally adequate. Because of its small leaves the Olive tree survives even extended dry periods, however they do not tolerate overly wet winter conditions.
Fertilizing Olive trees with nitrogen has proved beneficial. It is best to apply
fertilizers before the time of flowers develop so the trees can absorb the nitrogen before fruit set. Don’t forget to not over indulge on nitrogen as this will give you more leaves than fruit. Applications of potassium and phosphorus is also useful thinning the crop will give larger fruit size. This should be done as soon as possible after fruit set. Thin until remaining fruit average about 2 or 3 per foot of twig. The trees reach bearing age in about 4 years. When pruning, it is wise to avoid pruning during the rainy season, however they will tolerate radical pruning, so it is relatively easy to keep
them at the desired height that is best for you. Pruning regulates fruit production and shapes the tree for easier harvest. Fruit is generally borne on the previous year’s growth.
Olive fruits that are to be processed as green olives are picked while they are still green but have reached full size. They can also be picked for processing at any later stage up through full ripeness. Ripe olives bruise easily and should be handled with care. There are several classical ways of curing olives. Home production of Olive oil is not recommended. The equipment required and the sheer mass of fruit needed are beyond
Fruiting olives in the landscape are easy to grow however it it important to be mindful to keep them away from paved areas to avoid stains from fallen ripe fruit. They are known to have fewer pests than other fruit trees and deer seem to shy away form them. With their grayish foliage, Fruiting Olives can serve as a stunning accent and specimen plant. If one does not have open ground to plant in, they can be grown in a large decorative
container, and even be sculptural bonsai. Olives will beautify your yard or landscape when you pair similar plants that require the same needs and look good together such as: Pomegranate, Citrus, Rosemary, Sweet Bay, Lavender, many types California Natives, Sages, Boxwood, Indian Hawthorn, Iceberg Roses, Italian Cypress, and certain ornamental grasses. They are ideal for using as a focal point in a Mediterranean style garden. These stately and impressive trees provide an excellent design feature to ones garden even if it as simple as a few choice and select boulders strategically placed under the tree. If interested you can cultivate Fruiting Olives in your garden orchard by way of a system called SHD (Super High Density). This technique involves training your Olive on a trellis system and planted in rows running north to south to maximize canopy exposure. The 3 most common varieties used for this method are Arbequina, Arbosana, and Koroneik (see below for variety descriptions). Because they are the smaller growing ones and easier to keep them trained, you can plant them between 4 and 6 feet apart on center .You can keep them as tall and as wide that is manageable for you. Most plantings today are on a two wire system with the olives trained and tied up to the structure. Oftentimes this method is used by commercial growers but could be adapted to a smaller scale home orchard.
The flowers are largely wind pollinated with most Olive varieties being self-pollinating. Fruit set is usually improved by cross pollination with other varieties. Since many Olive cultivars are self-sterile or nearly so, they are generally planted in pairs with a single primary cultivar and a secondary cultivar selected for its ability to fertilize the primary one. The below olives are all considered a self-pollinating but produce higher yields with a pollinizer where noted. The Olives below produce a crop between late September and November. Please note the listed varieties may not always be available due to high demand, please call ahead and inquire about specific availability.
Introducing Manzanillo which produces large, rounded-oval fruit. The Skin is brilliant purple, changing to deep blue-black when mature. This Olive resists bruising and ripens early, several weeks earlier than Mission. The pulp parts readily with its bitterness and is exceedingly rich when pickled. Manzanillo is excellent for oil and pickles. This selection has a spreading form, is a vigorous grower, and a prolific bearer of medium sized fruit. It is the classic table Olive that can be eaten both green and ripe black. This variety becomes fruitier and less bitter as it ripens.
The Mission Olive is a medium-sized with oval fruit. The skin is deep purple changing to jet-black when ripe. The flesh is very bitter but firm and ripens rather late. This variety is good for pickling and oil. It is the most widely used for cold-pressed Olive oil in California. It is a vigorous grower, heavy-bearing, and more cold resistant than other cultivars. Mission Olive is the classic California Olive and this variety is the most versatile for the home garden because of its erect habit and medium density canopy.
Arbequina AS1® Olive
Arebequina has become California's top variety for oil production. The flavor is often described as mild with low bitterness, sweet, delicate, and the fruit is very high in oil content. Arbequina has a compact, upright growing habit. Arbequinea Olive is also a Spanish variety. For higher yields use Arbosana to pollinate.
Arbosona L43® Olive
This variety is mainly grown as a complement to Arbequina, and has a more robust flavor than that one. Arbosana Olive is a compact grower that is moderately frost hardy.
Even though the olives are small, it provides you with large crops of premium quality high-character oil. For higher yields use Arbequina or Koroneik as a pollinator.
Koroneiki I-38 Olive
Meet Koroneiki Olive who is from Greece and originally cultivated on the plains, lower hillsides and coastal areas of Crete where the climate is relatively warm. It adapts well in high density orchards. This selection produces a very small fruit but has an excellent oil quality with very high polyphenols. The fruit yield is high with a slight tendency for alternate bearing. Arbequina Olive is a compatible pollinator.
This old Italian variety called Pendolino Olive is used mainly as a pollinizer for other varieties, however for landscaping it offers many desirable characteristics such as good cold hardiness and a dense, weeping canopy and must be paired with another variety such as Frantoio. Though small, the Pendolino Olive produces a moderate amount of good quality fruit after 2-3 years old. The oil has a very mild flavor, low bitterness, and delicate pungency.
Now the Frantoio Olive is most commonly the main component for a Tuscan style oil. It consistently produces a high yield, very fruity oil and medium size fruit.
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