One aspect of the present invention is a sprayable composition for coating pipe for protecting it from one or more of root intrusion or root growth when the coated pipe is placed underground. Such sprayable formulation includes a 2,6-dinitroaniline herbicide; a polymer pellet impregnated with a 2,6-dinitroanililne herbicide-sorbed colloidal clay; and a film-forming polymer. Another aspect is pipe coated with the dried residue of a coating of a 2,6-dinitroaniline herbicide; a polymer pellet impregnated with a 2,6-dinitroaniline herbicide-sorbed colloidal clay; and a film-forming polymer, wherein the coated pipe is protected from one or more of root intrusion or root growth when the coated pipe is placed underground.