Abstract: A method for controlling the growth of plants, characterized by applying a plant growth regulator containing as active ingredient a benzenesulfonamide derivative represented by the general formula, ##STR1## wherein X is a halogen atom, an alkyl group having 1 to 5 carbon atoms, a nitro group, an amino group, an alkoxy group having 1 to 5 carbon atoms, an alkylthio group having 1 to 5 carbon atoms, an alkylsulfonyl group having 1 to 5 carbon atoms, or a group of the formula R.sub.3 CONH-- (where R.sub.3 is an alkyl group having 1 to 5 carbon atoms); n is an integer of 0 to 5; R.sub.1 is hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, a group of the formula --(A)--COOR.sub.4 [where R.sub.4 is hydrogen, an alkyl group having 1 to 5 carbon atoms, a cation such as Na.sup.+, K.sup.+, ammonium or a quaternary ammonium ion, and (A) is a group of the formula --(CH.sub.2).sub.m -- (where m is an integer of 1 to 3), or a group of the formula ##STR2## (where R.sub.5 and R.sub.