As a result of intensive urbanization processes, many urban ecosystems have undergone significant functional, morphological, and structural transformations. The introduction of inert, biologically inactive materials has influenced the alteration of land use and the functions of urban landscapes, thereby affecting the immediate natural resources (water, air, and soil). The degree of adaptation of a given plant species depends on the survival rate of its individuals, as well as on their ability to reach physiological maturity and the reproductive phase of the life cycle. The adaptability of plant species to new habitats (particularly urban ones) represents an important ecological indicator, as it reflects both the potential for broader utilization and the species’ relationship to native biodiversity. Urban ecosystems often encompass a considerable number of unmanaged (abandoned) and, from an ecological standpoint, impoverished habitats - urban fallows which are especially susceptible to biological invasions. Such urban areas are of great importance for monitoring the processes of adaptation and behavioural dynamics of individual plant species, especially those of alien origin, i.e., species introduced into urban environments through anthropogenic activity. It is well known that certain groups of plants (weedy, invasive, and others) possess a highly developed ability to occupy, colonize, and establish populations even within such specifically altered habitats. A systematic understanding of the mechanisms of adaptation and acclimatization of plant species in urban environments, particularly those introduced through human activity, along with an examination of their ecological impacts within urban ecosystems as dynamic systems constantly exposed to change, provides a foundational basis for ecological urban planning. The objective of this study is to highlight the complexity of relationships and interactions between the city, as a physical and inert system, and plants, as living and biological systems. The general systematization of knowledge about the mechanisms of adaptation and adjustment of plant species in urban environments, especially those introduced through anthropogenic activity, and the analysis of their impacts on urban ecosystems, which are dynamic and constantly changing, provides a foundation for the ecological planning of cities. This paper aims to highlight the complexity of the relationships and interactions between the city as a physical, inert system and plants as living, biological systems.