The present invention generally relates to a herbicidal formulation that comprises at least one phenoxy acid herbicide or an agriculturally acceptable salt or derivative thereof, and a surfactant adjuvant, wherein said surfactant adjuvant comprises at least one alkoxylated asymmetric alkylamine surfactant having the formula (I) wherein R1 is a straight or branched chain, saturated or unsaturated hydrocarbyl group having from 8 to 24 carbon atoms R2 is a C1-C4 alkyl group or a benzyl group A is an alkylene group containing from 2-4 carbon atoms x is 1-30 and y is 0-10 or a quaternised derivative of (I) having the formula (II) wherein R1 is a straight or branched chain, saturated or unsaturated hydrocarbyl group having from 8 to 24 carbon atoms R2 is a C1-C4 alkyl group or a benzyl group A is an alkylene group containing from 2-4 carbon atoms x is 1-30 y is 0-10 R3 is a C1-C4 alkyl group and Y− is an anion. The invention also relates to a method for controlling unwanted vegetation which comprises applying an effective amount of the aforementioned herbicidal formulation to said unwanted vegetation.
