Prunus spinosa of the fruit caused by the fungus "Taphrina pruni" produces an elongated and flattened gall, devoid of a stone. The shrub, with its savage thorns, is traditionally used in Britain and other parts of northern Europe to make a "cattle-proof" hedge. The fruit is similar to a small damson or plum, suitable for preserves, but rather and for eating, unless it is picked after the first few days of autumn frost. This effect can be reproduced by freezing harvested sloes. The juice is used in the manufacture of fake port wine, and used as an to impart roughness to genuine
Prunus americana Prunus americana Prunus americana, commonly called the American plum, wild plum, or Marshall's large yellow sweet plum, is a species of "Prunus" native to North America from Saskatchewan and Idaho south to New Mexico and east to Québec, Maine and Florida. "Prunus americana" has often been planted outside its native range and sometimes escapes cultivation. It is commonly confused with the Canada plum ("Prunus nigra"), although the fruit is smaller and rounder and bright red as opposed to yellow. Many cultivated varieties have been derived from this species. It forms an excellent stock upon which to graft the domestic plum.