The Wil Plum (Prunus americana) or Common Wild Plum, or American Plum, Marshall's Large Yellow Sweet Plum, has been found in every state of the union except Texas, California, Oregon, Nevada, Idaho, Hawaii and Alaska. It has been very generally confounded with the Canada Plum. The fruit is smaller, rounder than that of the Canada Plum and bright red in color.photo Many cultivated varieties have been derived from this species, as it quickly responds to the gardener's care; it also forms an excellent stock upon which to graft the domestic plum.