Buckthorn species are native to the middle east and Mediterranean area. They are the fruit of Rhamnus catharticus. Buckthorn berries are also known as Persian Berries, Avignon Berry or French Berry. Depending on the ripeness of the fruit different colors can be obtained. The green berries give a yellow color the ripe berries give a green color. The coloring agents in Buckthorn are flavonoids. Buckthorn berries cannot be used by themselves for coloring purposes, mordants must be added. The green berries will yield yellow hues with aluminum mordant, tin mordant will yield orange hues copper and iron mordants yield olive hues.