There are three varieties of blueberries — northern highbush, southern highbush, and rabbit eye. Traditionally, blueberries have been grown most successfully in Canada and the northern U.S. using northern highbush varieties. This plant type needs a high number of chilling hours.
However, in recent years, much work has been done using southern highbush and rabbit eye varieties to produce plants that will tolerate the low amount of chilling hours common in many parts of California.