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
Green rosella eucalypts—forming the bulk of its diet; other items eaten include the seed of the soft tree fern ("Dicksonia antarctica"), cranberry heath ("Astroloma humifusum"), myrtle beech ("Lophozonia cunninghamii"), Australian blackwood ("Acacia melanoxylon"), silver wattle ("Acacia dealbata") and buttercups ("Ranunculus"), berries, nuts and fruit, as well as flowers and new buds of southern sassafras ("Atherosperma moschatum"), mānuka ("Leptospermum scoparium"), shining tea-tree ("Leptospermum nitidum"), swamp honey-myrtle ("Melaleuca squamea"), Tasmanian bluegum ("Eucalyptus globulus"), Smithton peppermint ("Eucalyptus nitida"), messmate stringybark ("Eucalyptus obliqua"), snow gum ("Eucalyptus pauciflora"), manna gum ("Eucalyptus viminalis"), small-fruit hakea ("Hakea microcarpa") and native plum ("Cenarrhenes nitida"). The green rosella has at times