A hybrid of sage obtained by spontaneous crossing of two close-related species of Salvia (S. officinalis and S. lavandulifolia subsp. lavandulifolia) was identified through the study of its essential oil. Its chemical composition was monitored throughout a complete phenological cycle and compared with the parental species. The hybrid presented intermediate characteristics regarding essential oil production and composition. Î±-thuyone (25.4â57.2%) and 1,8-cineole (15.5â55.1) were the most representative compounds of S. officinalis and S. Lavandulifolia, respectively. Both of them were also the major compounds of hybrid essential oil but in a considerably lower percentage (Î±-thuyone 13.6â23.6; 1,8-cineole 12.0â34.7). The study shows the influence of the plant phenology in the chemical composition of the essential oils. The major compounds decreased significantly in the three species during flowering stage.