Abstract: This invention relates to a herbicidal composition comprising an an effective amount of a compound of the formula: ##SPC1##In which Z is a hydrogen atom or a benzyl group optionally substituted at para-position with a halogen atom, R.sup.1 is either a group -OR in which R is an alkyl group having 1-12 carbon atoms, a cyclohexyl or a lower phenylalkyl group, or a hydrazino group, R.sup.2 and R.sup.3 represent a hydrogen atom, a benzyl group, a group --COR.sup.4 in which R.sup.4 is a phenyl, lower alkyl or anilino group or R.sup.2 and R.sup.3, together with the nitrogen atom to which they are attached, form a phthalimido or succinimido group, and their acid addition salts. This composition has in particular an inhibiting activity on the growth of some dicotyledons.