Walnut trees are native to California, flourishing there long before European or American settlers arrived. The California walnut industry, however, goes back just 150 years or so, to the introduction of nonnative varieties by the Spanish missionaries in the late 18th century.
The missionaries cultivated many old-world crops in their gardens and farms, and they would have known walnuts in Spain. But little is known about walnut growing in the missions. Unlike the more familiar grapes, oranges and figs, walnut trees were probably planted as much for shade and ornamental purposes as for nut production.
By the 1840s, other California landowners began planting walnuts in and around the coastal areas of Southern California and the Napa Valley in Northern California. A survey in 1868 indicated a total of some 31,000 walnut trees grown in 41 out of California’s 50 counties.
The man who did more than any other to promote early commercial walnut growing in California was Joseph Sexton, who settled in the Santa Barbara area in 1867 and began planting walnuts. Through selective breeding and experimentation, he focused on promising ‘soft-shelled’ varieties. Word of his developments spread, and soon other growers were planting Sexton’s superior seedlings. At about the same time, Nevada City nurseryman Felix Gillet began introducing walnut varieties from France.
Throughout the booming 1880s, walnut orchards sprang up throughout Southern California, which until 1920 produced 95 percent of the state’s commercial crop. To provide a centralized location for processing their nuts, growers began forming dozens of local cooperative marketing associations such as Diamond Walnut Growers, Inc. In July 2005, Diamond members voted in favor of a conversion of the agricultural cooperative into a stockholder-owned corporation, and Diamond Foods, Inc. was born. Diamond Foods stock trades on the NASDAQ National Market under the symbol “DMND.”