Black walnut is a large tree native to North America and also cultivated throughout Europe. For centuries, black walnut has been a source of food and wellness support for indigenous populations. Black walnut hull is astringent and tannic and can be infused, tinctured, encapsulated, or used as a dye for fabrics.Black walnuts are smaller, harder, and more pungent than the English walnuts sold in grocery stores. The hulls without the meaty kernels inside are used in traditional herbalism. Black walnut trees exude a sap that discourages growth of competing plants over their roots. Black walnut is a member of the Juglandaceae. This information is for education purposes, and is not intended to diagnose, treat, cure, or prevent any disease. This information has not been evaluated by the Food and Drug Administration.