Knotgrass was a plant with magical proprieties. It was used in potion-making, and was an essential ingredient in the making of the Polyjuice Potion, as well as in the brewing of the alcoholic beverage Knotgrass Mead. The Daily Prophet reported in its 29 November 1926 issue that an unusually dry season had lead to a shortage of knotgrass. Knotgrass could be found growing in the Forbidden Forest. Harry Potter and Hermione Granger struggled through a patch of it on their way back from their first meeting with Grawp, just before they and Hagrid were approached by the centaurs.