Plant · P-269

Chinese Yam

Dioscorea polystachya

Chinese Yam, also called Shan Yao, is the rare tuber that is both a genuine food staple and a first-rank medicinal herb at the same time - grated raw as the nagaimo of Japanese cooking, or used dried as a traditional Chinese tonic for the stomach and spleen. It is a true cold-hardy perennial that needs nothing lifted or stored over winter, unlike many other yam species. The one real challenge is the tuber itself: it grows two to three feet straight down and snaps easily on the way out of heavy clay, so it grows best in a deep raised bed of loose soil, or in a vertical harvest tube that comes apart at digging time. Its edible bulbils, forming along the vine, are ready to eat years before the tuber reaches full size.