Disclosed herein are herbicidal compositions comprising a herbicidally effective amount of (a) a pyridine carboxylic acid herbicide or an agriculturally acceptable N-oxide, salt or ester thereof, and (b) a synthetic auxin herbicide, an auxin transport inhibitor, agriculturally acceptable salts or esters thereof, or combinations thereof. Also disclosed herein are methods of controlling undesirable vegetation which comprise applying to vegetation or an area adjacent the vegetation or applying to soil or water to prevent the emergence or growth of vegetation (a) a pyridine carboxylic acid herbicide or an agriculturally acceptable N-oxide, salt or ester thereof, and (b) a synthetic auxin herbicide, an auxin transport inhibitor, agriculturally acceptable salts or esters thereof, or combinations thereof, wherein (a) and (b) are each added in an amount sufficient to provide a herbicidal effect.