In the early 2000s, I was very much involved in gardening, both my own and visiting other gardens, but I had no knowledge of olive trees being planted in Oregon. Not only were they not seen in local gardens, but they were also not readily available in local garden centers.

Olive trees were considered a Mediterranean plant that could grow in California and Arizona, but not in Oregon. Our winters were too cold and too wet — those were the commonly heard objections.

My opinion on growing olive trees in Oregon changed in 2008 on a visit to Red Ridge Farms in Dayton, Oregon. Olive trees were being planted as a commercial crop and there was even a state-of-the-art olive mill to press the olives for their oil, process it, and then offer it for sale.

Today, almost twenty years later, Durant at Red Ridge Farms has 17 acres of olive trees. Olive trees are now available at most local garden centers and in most cases, have seemed to grow well in our local conditions.

Many local gardeners have planted olive trees, including me. My garden has three ‘Arbequina’ olive trees. They have thrived in a location that receives very hot summer sun and very little supplemental water.

If olive trees can grow in home gardens — albeit mostly for ornamental purposes in Oregon thus far — are there cultivars that would produce enough fruit to make it viable and successful commercially? That is one of the questions that the Oregon State University North Willamette Research and Extension Center (NWREC) in Aurora, Oregon, is researching.

In July, 2021, the Oregon State Small Farms Program Joint Research Project planted 420 olive trees that included 118 distinct cultivars. These trees were all in one-gallon containers, so all were about the same size.

The trees were planted in an open field receiving full sun and no protection from the elements. When I asked Neil Bell, retired OSU Community Horticulturist, if this trial is the first and only Extension sanctioned olive trial in the Pacific Northwest, he said: “The plot is actually more unique than the Pacific Northwest.

“There really exists nowhere else in the world a replicated trial, (meaning more than one tree per cultivar), of so many olive cultivars, planted in one place at the same time and all of the same age,” he said. “It’s a unique planting for those reasons and gives us an opportunity to directly compare all of these 118 cultivars for growth, yield, fruit and oil characteristics as well as cold hardiness. We are only getting started.”

On a recent visit to this olive planting project, I visited with two other members of this project team: Heather Stoven and Hayley White. My visit was to coincide with the harvest.

Olive fruit from the trees in the trial would be collected, bagged, observed for color, size and then weighed. With so many cultivars available, it is necessary to sort through them and select those that both have cold hardiness and good fruit production.

 “The aim of our project is to support the emerging olive industry in Oregon by evaluating olive cultivars to determine which are best suited for our western Oregon climate” Stoven said. “Currently, the major obstacle for olive production in our region is winter injury to trees. However, we are keeping our eye on the emerald ash borer as a future pest. Along with rating cold damage each spring, we also collect plant size, flowering, and fruit data. We hope to be able to evaluate the oil characteristics of some of the olive cultivars in the future as well.”

Observing the difference in growth patterns in the trees was surprising. Considering that all were about the same size and were planted at the same time, differences in growth were remarkable. There were a few trees that looked as though they were struggling to survive, but most were in the 3–4 foot height range.

There were a few that were 5 feet or more. Most looked healthy.

“The olive industry is still very new compared to other crops grown in Oregon, and the only research available for our area is from this group,” White said. “Our goal is to help the producers in Oregon make informed decisions when planting olive trees to increase economic feasibility, giving farmers the tools they need to continue to make top quality olive oil while diversifying their farm.”

The OSU Aurora Extension Station has a yearly Oregon Olive School and olive field day, which is an excellent way to get more information on growing olive trees in Oregon. While this event is geared toward commercial growers, it can also provide information for interested home gardeners and local garden center owners.

Actually, in the past few years, local garden centers have begun to offer more cultivars for home gardens. The cultivar ‘Albequina’ has been the standard, but more cultivars are becoming available. Since most home gardeners are probably more interested in treating an olive as an ornamental tree, fruit production is less of a concern. With their soft gray green foliage, an olive tree can provide a striking evergreen winter foliage plant in the garden.

 What an exciting time for local garden centers! They get to attend an actual research field day to learn more about what additional cultivars of olive trees to stock for the discerning gardener.

Planting evergreen olive trees is a newer trend in planting ornamental trees, but one that local garden centers can take advantage of in a big way. Various cultivars of olive trees have been readily available in California for years. Now it is time for them to migrate to Oregon.

From the December 2023 issue of Digger magazine | Download PDF of article