Phytocoenotic conditions of growth and anthropogenic management of natural phytocoenoses have a significant impact on the population characteristics and stocks/reserves of medicinal plant raw material. The article presents the results of the peculiarities of the response of spatial, dimensional, ontogenetic and vitality structures of populations of the official species - Hypericum perforatum L., and establishes a dependence that allows predicting the reserves of medicinal plant material Hyperci herba by the height of individuals. With the aim of forecasting the dynamics of the resource potential of this species, geobotanical descriptions were conducted, and classical population methods were applied: morphometric, ontogenetic and vitality analyses, as well as a number of statistical methods (correlation, factorial, dispersion, and regression analyses). It was established that the population density of H. perforatum averaged from 3 to 12, but sometimes reached 20 to 30 individuals/m2, with the maximum observed under conditions of random mowing. The minimum indicators of the vegetative sphere: height of generative individuals (h, cm), aboveground phytomass (W, g), photosynthetic effort (LWR, %) were noted in populations used as hayfields, pastures, and in agrophytocenosis. The maximum indicators were in populations that were generally or almost unaffected by anthropogenic influences. Research on the dynamics of the main morphological parameters showed that while the maximum and minimum parameters of vegetative structures differed by approximately 2.1 times, generative parameters differed by 4.6 times. Statistically significant differences were observed among H. perforatum populations in terms of the number, mass of generative organs, and the reproductive effort of plants. A statistically significant correlation was found between plant height (h, cm) and the productivity of aboveground dry phytomass, which forms the herbal raw materials (HRM, g). It is described by the equation: HRM = 0.167h - 3.28. In hayfield-pasture areas and in agrophytocenosis, up to 60–75% of individuals were of small size and low vitality, their contribution to the production of medicinal plant raw material was insignificant. Overall, the conducted research showed that Hypericum perforatum L. exhibited significant phytocenotic diversity, which depended on a complex of ecologo-cenotic factors and types of anthropogenic management.