Wildroot

Wildroot is a crop added by Roots 2. It is obtained by placing 2 wheat, 2 poppies and a potato in a Moonlight Circle, as outlined in the Book of Herblore. When all items are at full growth, a light effect will be seen and the central item will be transformed into Wildroot. The crop can then be obtained by right clicking. Wildroot doesn't have a seed. It can be propagated by placing the crop itself on irrigated dirt.

Note that although the Book of Herblore states that this transformation takes place under moonlight, this doesn't seem to be the case.