Goat heads, Tribulus terrestris, are a noxious weed that grows in Crestone, as of 2015, near the intersection of Silver Avenue and Alder Street. Goat heads a a low plant with yellow flowers which develop into clusters of stickers with two thorns protruding from each sticker. Goat heads grow near the entrance to the post office and on the corners of the intersection of Silver and Alder. In 2016 work on curbs and gutters and sidewalks disrupted much of this intersection. It is unclear how much the infestation of Tribulus terrestris was affected. The weed is on the Colorado List of Noxious Weeds.