| Section2 = | Section7 = }} Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid)'s a selective herbicide used for control of broadleaf weeds, especially thistles and clovers. For control of Creeping Thistle, Cirsium arvense, a noxious, perennial weed, clopyralid's the only effective herbicide available. Clopyralid's in the pyridine family of herbicides, which also includes picloram, triclopyr, and several less common herbicides. It's particularly active on members of the Asteraceae and the Faba… (More on Clopyralid)