Growers Prepare for Harvest in Northern Frontier of U.S. Olive Oil Production

Olive grow­ing in Oregon is often called the new fron­tier. Frontier farm­ing is typ­i­cally known for both pit­falls and promises.

“Oregon trees are far­ing well this sum­mer,” Heather Stoven, from Oregon State University’s agri­cul­tural exten­sion ser­vice, told Olive Oil Times. ​“Established olives in Oregon can tol­er­ate the heat and dry sum­mer con­di­tions with­out pro­tec­tive mea­sures. Young trees, how­ever, do need sup­ple­men­tal water dur­ing the sum­mer.”

“Interest in grow­ing olives in Oregon has been strong due to the warmer and drier sum­mers we have been expe­ri­enc­ing – espe­cially for those who have water avail­abil­ity issues,” she added. ​“The crop is well suited for increased heat and drought.”

Stoven explained that cold spells in win­ter are the most sig­nif­i­cant risk to grow­ing olives in Oregon. Even with hot, dry sum­mers, if the trees expe­ri­ence exten­sive dam­age dur­ing the pre­vi­ous win­ter, they will not pro­duce well.

Interested pro­duc­ers must eval­u­ate areas to find a favor­able site and micro­cli­mate to grow olives in Oregon.

“My par­ents started the vine­yard oper­a­tion and really are entre­pre­neurs,” Paul Durant, co-owner and founder of Durant Olive Mill in Dayton, told Oregon Public Broadcasting. ​“We became pas­sion­ate about olive trees and planted a few thou­sand trees around 2004/05.”

Since then, ​“we felt like we were hav­ing a lot of suc­cess and went even big­ger and built a mill,” Durant said.

“After a series of tough set­backs and hard win­ter con­di­tions plus a big freeze in 2013, we were forced to rethink and re-look at what are the good vari­eties for Oregon,” he added.

The Durant Olive Mill is state-of-the-art. The olive har­vest and milling occur each autumn with a blend of olives from Durant’s Oregon groves and care­fully-sourced olives from select grow­ers in Northern California.

According to Stoven, the exact num­ber of grow­ers in Oregon is approx­i­mately less than 50, most of whom grow olives for oil pro­duc­tion. Most of the state’s olive grow­ers are located in the Willamette Valley, with a few in Southern Oregon.

However, inter­est is high in Oregon State University’s Olea project, which is study­ing which olive trees are best suited to thrive in Oregon’s cli­mate con­di­tions. The Olea project was estab­lished to research and eval­u­ate best prac­tices for table and oil-pro­duc­ing olives in Oregon.

Challenges for olive farm­ers in Oregon are not lim­ited to weather and cli­mate change. Stoven noted that the emer­ald ash borer is a pest that has been recently dis­cov­ered in Oregon. ​“This pest has the abil­ity to dam­age olive trees. However, at this time, we are unsure exactly how severely olives will be affected,” she said.

In June 2022, state offi­cials in Oregon con­firmed the dis­cov­ery of an emer­ald ash borer, an exotic bee­tle that infests ash trees, in Forest Grove, just west of Portland. This marked the first con­fir­ma­tion of the inva­sive pest on the United States West Coast.

Oregon pro­vides an online hot­line to enable res­i­dents and vis­i­tors to report a poten­tial inva­sive species. The pub­lic can use this form to help iden­tify this poten­tially dan­ger­ous pest to inva­sive species experts.

According to Entomology Today, the olive tree is the sec­ond non-ash species found to be vul­ner­a­ble to emer­ald ash borer. In a detailed study from Wright State University, the emer­ald ash borer can develop from lar­vae to adult­hood on a species of olive trees.

“If emer­ald ash borer can detect and uti­lize olive trees in the field, it would take it from being pri­mar­ily a for­est and land­scape pest to a poten­tial crop tree pest,” Don Cipollini, a pro­fes­sor of plant phys­i­ol­ogy and chem­i­cal ecol­ogy at Wright State and lead author of the study, told Entomology Today.

Hobby grow­ers and pro­fes­sional pro­duc­ers are opti­mistic about the upcom­ing har­vest. ​“Oregon’s har­vest is look­ing promis­ing,” Stoven said. ​“At this point in the sea­son, the trees have bloomed, and fruit is on its way. Olive grow­ers should con­tinue to mon­i­tor plant health and nutri­tion.”

Olive tree irri­ga­tion, fer­til­iza­tion and mon­i­tor­ing remains a key issue. In addi­tion, pro­duc­ers need to develop a plan for attract­ing farm work­ers, as olive har­vest­ing in Oregon depends on proper hand-pick­ing.

“Machine har­vest­ing in Oregon, given the wet con­di­tions that we’re pick­ing in, is prob­a­bly never going to hap­pen, cer­tainly in my life­time,” Durant said.

Stoven agreed: ​“Labor for har­vest can be an issue; there­fore, devel­op­ing a har­vest plan is an impor­tant step before the end of the sea­son.”

“Olives are a small niche crop in the state, pro­duc­ing a high-qual­ity oil which is sought by those look­ing for locally pro­duced spe­cialty foods,” Stoven said. ​“We will not com­pete with California, for exam­ple, due to our cli­mate lim­i­ta­tions.”

Most of the olives in Oregon are grown in the Willamette Valley. This val­ley is well-known for its tem­per­ate cli­mate, mak­ing it a prime wine-pro­duc­ing region.

According to Oregon Wine, the Willamette Valley is Oregon’s old­est wine region, with two-thirds of the state’s winer­ies and vine­yards. It is home to more than 700 winer­ies, and its Pinot Noir is leg­endary. The val­ley is about 240 kilo­me­ters long, framed by the Coast Range to the west and the Cascade Mountains to the east.

“Cool win­ter tem­per­a­tures in Oregon limit olives to areas west of the Cascade Mountains,” Stoven said. ​“Areas of south­ern and east­ern Oregon can have hot­ter sum­mers than the Willamette Valley (where most of the olives are grown).”

“However, most of these areas are colder in the win­ter and there­fore not able to grow olives,” she added. ​“There are a few areas of south­ern Oregon where olives are grown, but not all areas are suit­able.”

• Entomology Today
• State of Oregon
• Oregon Public Broadcasting