Dioscorea japonica Japanese Mountain Yam (Yamaimo)
A twining, perennial climber with attractive, heart-shaped foliage and small, white, autumn flowers that is native to Japan, China, Korea and Assam. Produces tubercles in the leaf axils. Hardy in the UK. Height 3 m. Humus rich, well-drained, moisture retentive soil in sun to light shade.