Yellow dock, also known as curly dock, sour dock and garden patience, is a short-lived perennial herb that is native to Europe and Africa. At one time, the curly leaves of the plant were eaten as a vegetable for tonic purposes. That is no longer common practice, however.
The plant is harvested for its root in late summer, after its seeds have turned from green to deep red. As the common name implies, the root of the herb is yellow.