Swan Hill Nurseries

The Swan Hill Story

In 1962, Dr. Hudson T. Hartmann, Ph.D. of the University of California, Davis, CA discovered a non-fruiting olive cultivar near the town of Swan Hill in Northern Victoria Province, Australia. According to the orchard owner, the tree was at least 30 years old and while it had flowered, no fruit had ever been observed. After studying the cultivar an additional 8 years in Davis, Dr. Hartmann in conjunction with the University of California’s Office of Technology Transfer applied for a plant patent. Federal Plant Patent number 3197 was awarded to the Swan Hill Olive variety on the basis of its unique non-fruiting qualities. Swan Hill Nurseries, LLC (formerly R&G Trees) purchased propagation rights in 1979. When the plant patent expired, in 1989, Tom Russell, Ph.D. and Swan Hill Nurseries, LLC applied for and were granted a United States Registered Trademark No. 2,001,332 for the Swan Hill Olive^®.

Pollen

In the 1980’s public health concerns about allergenic pollen lead Pima County (Tucson), Arizona to pass an ordinance banning the importation and sale of the Common European Olive within the boundaries of the County. Other communities, including most municipalities of Maricopa County (Phoenix), Arizona, Pima County (Tucson), Arizona, Clark County (Las Vegas), Nevada and Hemet, California, have adopted similar ordinances. The Swan Hill Olive^®, as grown by Swan Hill Nurseries, LLC, is exempt from all of these ordinances.

In response, Swan Hill Nurseries, LLC (formerly R&G Trees) sponsored a research program to determine whether or not the Swan Hill Olive^® should fall within the new ordinance. Drs. O’Rourke, Ph.D. (The University of Arizona) and Buchmann, Ph.D. (U.S. Dept. of Agriculture) under the direction of the University of Arizona College of Medicine undertook the study. O’Rourke & Buchmann’s research concluded that the Swan Hill Olive^® "yielded little, if any, airborne pollen." Their results were published in two refereed scientific journals(a). These results were later confirmed other researchers (a).

Verticillium Wilt

Verticillium Wilt is a devastating disease of many plants caused by the fungus Verticillium albo-atrum. European Olive is very susceptible to this disease and once infected trees slowly decline and eventually die. Symptoms include leaf drying and browning, wilting or "flagging" of entire branches. Over time the fungus spreads to other parts of the tree. Removal of affected limbs will not stop the spread, as the fungus is present in the root system. Infected trees may not express symptoms until years after they have been planted and have become focal points of the landscape design.

The Swan Hill Olive^® has reduced the risk of this devastating disease by grafting our trees onto the Verticillium Wilt Resistant rootstock called "Oblonga" (Olea europaea cv. "Oblonga"). The cultivar "Oblonga" was identified by Hartman, Schnathorst & Whisler of the University of California at Davis and the United States Department of Agriculture, respectively, to be resistant to Verticillium Wilt. In a 16 year study researchers reported…"[olive] growing on the Oblonga clonal rootstock remained free of symptoms."

Look for the Tags

When you see the Swans, everyone breathes easier.

We are proud of the trees we grow and so confident in their unmatched qualities of non-fruiting, non-pollinating and wilt resistance that we place a uniquely numbered tag on each one. This tag assure you that you that the tree you purchased is the premiere landscape olive on the market; The Swan Hill Olive®. It confirms that the olive trees you plant are exempted from community policy restricting pollen producing olives. Look for the tags. If you don’t see the Swans, you didn’t get The Swan Hill Olive®.