When I first moved to Napa Valley many years ago, olive trees were everywhere, both on the hillsides and in the valley. There was a large grove high on a hill on Silverado Trail, but over the years those trees have disappeared. I have seen olives being moved to new locations on the trailers of huge trucks, their roots encased in large boxes. They seem to survive these moves very well.
When my husband and I moved to our home, someone in the neighborhood had an olive tree that bore fruit. Olive seedlings were coming up all over our small field and yard. We potted up some of these seedlings and pulled up some. One of them is still in the ground. However, these trees that sprouted from olive pits have never borne fruit themselves.
Olive trees came to California from Spain with the Spanish missionaries. They planted olive trees in 1769 at the San Diego mission. When the first Italian settlers came to the Napa Valley, they also brought olive trees with them.
The first olive trees planted in the New World were planted in Peru. The missionaries planted them at every new mission, not only for food but for oil. In fact, the English word oil is derived from the Greek word for olive.
The early Romans spread olive trees throughout the Mediterranean, planting them in lands they conquered. They used the olives for food and for their precious oil. It is estimated they planted 50 to 60 million trees over the life of the Roman empire.
Olives need some irrigation when young but, once established, they grow well in most soils without water. It has been said that olive trees thrive with drought, sun, rocky soil, silence and solitude. They also need a Mediterranean climate, which Napa Valley provides.
Lila Jaeger, who was a Napa County Master Gardener before her death in 2001, discovered century-old olive trees on the property where she and her husband established Rutherford Hill Winery in 1976. The trees had been neglected and were in bad condition. Lila took on the task of getting them back in shape. For a while, the winery harvested the olives and made oil for sale in the tasting room.
Laddie Hall, another Napa County Master Gardener, found 450 olive trees at the Long Meadow Ranch property she and her husband, Ted, purchased in 1989. These trees, too, had been planted more than a century prior and neglected over the years.
The Halls have worked to bring these trees back to good health. They sell oil from the olives and have sent samples of the trees to a lab in Spain to try to identify the varieties, unfortunately with no success. They have planted additional acreage and now have over 1,400 olive trees growing on their St. Helena property.
While olive trees are grown in other states, California accounts for 98 percent of U.S. production. Some citrus growers are replacing diseased citrus trees with olive groves.
Olives are easy to propagate from cuttings. The biggest cutting I ever took was from a large limb on the seedling tree growing on my property. It is several years old now and has made a wonderful bonsai. I did not realize how hard olive wood was until I carved it with my die grinder and ruined the bit.
When I take cuttings from olives, I plant them in a mixture of sharp sand and pumice that drains quickly but also retains moisture. I tried propagating cuttings in my cloner, but it kept the cuttings too wet.
If you would like to plant an olive tree, pick a sunny spot with good drainage. It will need some water until it is established. Olives are wind pollinated. In ancient times, the fruit was food for the poor but olives are now used in many gourmet recipes.
Olives are harvested in the fall and winter. Even ripe olives are too bitter to eat right off the tree. They must be processed to remove the bitterness. There are several methods for doing so, including a water cure, a brine cure and a lye cure. You can find directions for curing olives online, but all the people I know who grow olives send them to professionals for this treatment.
Library Talk: Join UC Master Gardeners of Napa County for “What's Hot in Compost” on Thursday, July 7, from 7 pm to 8 pm, via Zoom. Learn about successful composting: what to add, when to harvest and what about those worms? We'll discuss how “hot” composting works and why to try it. The talk is free. Register to receive the Zoom link at
Food Growing Forum: Join UC Master Gardeners of Napa County for a free forum on “Integrated Pest Management” on Sunday, July 10, from 3 pm to 4 pm via Zoom. Learn about IPM and what to do in the July food garden. Register to receive the Zoom link at https://ucanr.edu/2022FoodForumJuly
Gardening with the Masters: Join UC Master Gardeners of Napa County and Ole Health on Saturday, July 16, from 10 am to 1 pm at Ole Health South Campus, 300 Hartle Court, Napa, for a workshop on gardening. Children five years old or older, accompanied by an adult, are welcome. Attendance is limited. Register here: https://www.olehealth.org/our-services/community-outreach-resources
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