Evaluating the adaptability and field longevity of medicinal plants is important for their domestication and economical production, especially in areas with harsh environmental conditions where many crops fail to grow. In this agroecological comparison, samples of Mentha longifolia were collected from two natural habitats in Iran, from 1999-2004. Then, samples were planted at the Research Institute of Forests and Rangelands, Tehran, Iran, and were evaluated during six years. Results indicated that the two populations varied in their essential oils content and composition. Moreover, all the measured traits were significantly different during the different years. Population one had higher leaf and flowering shoot essential oil yield and flowering shoot yield. Among the years, plant height (111.63 cm) and the number of lateral branches (36.66) were the highest in the first year. However, the total essential oil yield (21.51 kg/ha) and flowering shoot yield (3029.66 kg/ha) were the highest in the fourth year. GC and GC-MS analysis detected carvone as the main compound in both populations (72.3% in population one and 62.3% in population two). Results of this experiment briefly indicated that M. longifolia produces the highest biomass and essential oils yield up to the forth year
