Orris Root (Iris x germanica) is the root of some species of iris, grown principally in southern Europe: Iris germanica, Iris florentina, and Iris pallida. It is used mainly as a fixative and base note in perfumery.
After an initial drying period, which can take five years or more depending on the use, Orris Root is ground. For potpourri, this powder is used without further processing. For other uses, it's dissolved in water and then distilled. One ton of iris root produces two kilos of essential oil, also referred to as orris root butter, making it a highly prized substance, and its fragrance has been described as tenaciously flowery, heavy and woody.