Epimedium, also known as Rowdy Lamb Herb, Barrenwort, Bishop's Hat, Fairy Wings, Horny Goat Weed, or Yin Yang Huo, is a genus of about 60 or more species of herbaceous flowering plants in the family Berberidaceae. The large majority are endemic to southern China, with further outposts in Europe, and central, southern and eastern Asia.

Epimedium species are hardy perennials. The majority have four-petaled "spider-like" flowers in spring. Many are believed to be aphrodisiacs, particularly horny goat weed.

Epimedium are only just beginning to garner attention in the West. While they vary somewhat in their respective hardiness, all are essentially dwellers of the forest floor, and, as such, all require fundamentally similar conditions of moist, free draining, humus rich soil and cool shade, with some shelter for the newly emerging leaves.