The genus Mentha includes aromatic herbs that produce essential oils used in medicine, flavor, and fragrance. Elite peppermint cultivar Black Mitcham (M. × piperita) is highly valued for its oil quality but vulnerable to the soil-borne fungal pathogen Verticillium wilt. Black Mitcham is also sterile, hampering improvement efforts based on conventional breeding strategies. In this study, we describe the restoration of fertility in Black Mitcham through colchicine-induced chromosome doubling. Furthermore, we explore the potential to produce disease-resistant hybrid clones with desirable oil profiles through interspecific hybridization with Verticillium-resistant spearmint (M. spicata) clones. Seven clones of colchicine-treated Black Mitcham previously identified as genome-doubled (12x) were evaluated, with five identified as chimeric and two fully genome-doubled. All treated clones displayed increased fertility, evidenced by the presence of viable pollen and seed production, enabling crossbreeding to spearmint (4x) to produce octoploid hybrids (8x). Eleven hybrids were identified. Verticillium resistance trials indicated that three hybrids potentially exhibited increased resistance while four were susceptible. Gene dosage analysis of resistant and susceptible hybrids revealed potential chromosomal regions associated with this trait. Further investigation into these regions could lead to the identification of resistance genes and the development of molecular markers for marker-assisted selection (MAS).