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Knotgrass
Species information
Usage	Ingredient in Polyjuice Potion ; Ingredient in Knotgrass Mead ;

"This is the most complicated potion I've ever seen. Lacewing flies, leeches, fluxweed, and knotgrass. Well, they're easy enough."

—Hermione Granger about the Polyjuice Potion ingredients, including knotgrass.^[src]

Knotgrass is a plant with magical proprieties. It is used in potion-making, being an essential ingredient of the Polyjuice Potion and in the brewing of alcoholic beverages such as Knotgrass Mead.

Knotgrass can 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.

Behind the scenesEdit

Knotgrass may refer to several species of the Polygonum genus found in England and Europe. It is most likely Polygonum aviculare, which was believed to halt the growth of animals and was mentioned as such in the works of Shakespeare.^[1]
The use of knotgrass in the Polyjuice Potion was chosen by J. K. Rowling to represent "being tied to another person".^[2]

Knotgrass

Species information
Usage	Ingredient in Polyjuice Potion Ingredient in Knotgrass Mead