PNW to S. Calif.
"Often the first deciduous native shrub to flower in late winter, Indian plum is an important early season nectar source for hummingbirds, moths and butterflies, native bees and other pollinator species...
Various small mammals plus foxes, coyotes, deer, bears, and many bird species consume the ‘plums’ and disperse the seed. For livestock, this species is considered unpalatable." 
"Indian plum fruit is edible for humans but is often bitter, even when fully ripe. Native Americans ate the fruit fresh, dried, or cooked. The bark was used as a tuberculosis remedy and a mild laxative. Strips of bark were used to bind harpoon tips." 
"Indian plum is popular for Pacific Northwest restoration projects due to its ease of propagation, rapid growth, and wide tolerances for various shade and moisture regimes. The fibrous roots resist erosion. Clones that root more readily can be employed in restoration projects as live stakes or as rooted cuttings."