Whispergrass is a plant that grows only on the shores of bodies of water where merpeople live. The reason, discovered in 1698 by Elladora Ketteridge, is that a mineral crucial to the survival of the grass, veratoma, is only present in the perspiration of merpeople. Physically similar to lemongrass, whispergrass is so-named for the distinct sounds, resembling whispered human speech, that it makes when rustled by the wind. Strangely, observers tend to disagree on what, exactly, they hear on the breeze.
Whispergrass grows lushly along the southern shore of the Black Lake on the campus of Hogwarts School of Witchcraft and Wizardry, and has become a staple food-source for the colony of firelarks that live in the Forbidden Forest. Several additional magical properties of the grass were discovered by Neville Longbottom following his appointment as Hogwarts' Professor of Herbology in 2008.