Juglans californica shell that is difficult to remove. The Chumash Indians of the Channel Islands of California and Ventura County eat the nuts; however, they are not grown commercially for this purpose. "Juglans californica" is cultivated throughout California to support the walnut industry, used as a rootstock in English walnut orchards. It is also cultivated as an ornamental tree where it is planted in California native plant, xeriscape, and wildlife habitat gardens and natural landscaping in California, and in Hawaii. Some authorities (e.g. the California Native Plant Society) combine this species with "J. hindsii". On the other hand, a 2007 molecular analysis
Fruit tree propagation cultivars of a single species, known as a family tree, or, within certain limits, cultivars of different fruit species on one tree, often known as a fruit salad tree. Family trees typically combine several cultivars (two or three being most common) of apple, pear or a given species of stonefruit on a single rootstock, while fruit salad trees typically carry two or more different species from within a given genus, such as plum, apricot, and peach or mandarin orange, lemon, and lime. Certain combinations, including sour cherry ("prunus cerasus")/sweet cherry ("prunus avium"), although from the same genus, are known to