Relevance. Oenothera tetragona is an ornamental plant used in folk medicine. Until now, studies of the biological characteristics of the Oenothera tetragona have not been carried out on the territory of the NonChernozem zone of the Russian Federation.The purpose of the work is the introduction and biological study of the Oenothera tetragona in the NonChernozem zone of Russia in the conditions of the Moscow region.Methodology. The experiment was based on two-month-old seedlings according to a 60x30 cm pattern. Phenological observations and biometric measurements (during the mass flowering phase) were carried out according to the methods adopted at VILAR (All-Russian scientific research Institute of medicinal and aromatic plants). Experimental data were processed according to B.A. Dospehov. Weather conditions were checked on the Weather and Climate website. Microspecimens were prepared according to methods for light microscopy.Results. In the conditions of the Moscow region the period from the beginning of the growing season to mass fruiting in Oenothera tetragona Roth. averages about 110-115 days. The plant is well adapted: it goes through the entire seasonal cycle of growth and development. The population includes Oenothera tetragona Roth. includes many variable biotypes, which indicates the possibility of targeted selection of forms with useful traits. The main assessment of breeding material can be carried out, starting from the second year of plant life, based on a set of interrelated quantitative traits (height, number of generative shoots, etc.). Some anatomical features of the epidermis of the Oenothera tetragona leaf have been studied for the first time; the number of covering trichomes and the number of stomata per 1 mm2 were determined. As a result of microscopic examination of the epidermis of leaf plates of O. tetragona Roth.: the presence of three groups was revealed, which differed in microscopic characteristics (shape and number of stomata, pubescence) in the absence of a noticeable correlation with the main phenotypic characteristics.