The sex structure and seed productivity of Mentha canadensis L. from different climatic regioins of Primorye of Russia was studied. We established that M. canadensis is characterized by a homogeneous population structure due to the formation of vegetative clones. The ratio of female and androgynous individuals was 1:5, and it is possible that this is a species-specific trait. Both sexual forms produced fruits under conditions of isolation from cross-pollination. We discuss the possibility of apomixis and the influence of climatic conditions on seed productivity and morphometric characteristics of plants.