Gardeners Prompt Change in Julian's Climate Zone
By Tom Gorton

Julian gardeners Sally Snipes, left, and Carol Jacklin recently helped the editors of the "Sunset Western Garden Book" reassess the climate designation and other information concerning the Julian area. Photo by Tom Gorton

When it comes to choosing plants for different geographical areas, many gardeners let their green thumbs do the walking and rely on the "Sunset Western Garden Book" for advice on what to grow.

But when Sunset changed the climate zone for Southern California's interior mountains in 2001 from a Zone 3 to a Zone 18, Julian gardeners Carol Jacklin and Sally Snipes objected.

Their efforts during the next five years helped Sunset reassess the climate designation for Julian and San Diego's interior mountains to a Zone 7 in the 2007 eighth edition of the 768-page tome.

"Many of us here (in Julian) grow apples, pears and peonies that need a brisk winter chill and simply cannot be grown down the hill in the hotter inland valley areas of Zone 18," Jacklin said.

Zone 18 scoops in places such as San Bernardino, Hemet and a narrow belt that runs southeast of Valley Center toward Alpine.

When Jacklin and Snipes learned in 2001 that Sunset had reclassified Julian from a Zone 3 to a Zone 18, they approached Jim McCausland, a longtime senior editor and writer for Sunset who sets the zones for the "Western Garden Book."

"He responded immediately and asked for specific weather records describing Julian's climate and plants that are borderline here," Jacklin said.

"For example, he wanted to know if avocadoes grow in Julian, and the answer was obviously 'no.' We can grow deciduous magnolias here, but not evergreen magnolias. We grow an immense variety of apple trees that are not productive in hotter areas. We can grow birch trees in Julian if we give them enough water, but water, of course, is the issue."

In addition to borderline plants, Jacklin and Snipes provided Sunset with weather data gathered from the California Department of Forestry and several local sources.

"Julian is a tricky place to garden because a remarkable range of temperatures, rainfall and soil types have created microclimates here," said Snipes, a local artist whose community work over the past seven years has resulted in the planting of more than three million daffodil bulbs.

Through their efforts to answer McClausland's questions, Jacklin and Snipes became consultants to the "Sunset Western Garden Book." But their biggest achievement, they said, was getting Julian reclassified from a Zone 18 to a Zone 7, which Jacklin considers an appropriate classification

"Because there are so many different climate zones assigned to specific plants, some classifications are crucial to the success of gardening," Jacklin said. "While the American Horticultural Society sets climate zones based on heat, the U.S. Department of Agriculture determines zones based on cold," she pointed out.

Many gardeners consider the "Sunset Western Garden Book" as the bible for gardening in the west because it establishes zones based on a combination of heat and cold.

Now all three authorities - the USDA, Horticultural Society and "Sunset Western Garden Book" - classify Julian and Southern California's interior mountains in Zone 7.

"Carol and Sally had much to do with the change to Zone 7, which I'm confident is correct," McCausland said. "They encouraged me to look harder at the raw climate data we had, supplemented it with data we didn't have, and checked plant lists for us. They were definitely the most important climate checkers in the current edition."