The increase in the biological diversity of northern cities requires in-depth studies on the adaptation of introduced species to unfavorable factors of the winter period. This type of stability depends on many factors, the decisive of which are genetic properties, the correspondence of seasonal development to the climatic characteristics of the region, the degree of preparedness of plants for the winter period and the characteristics of winter. The article presents the results of the assessment of frost resistance and winter hardiness of extrazonal and introduced dendroflora. Their preparedness for winter has been studied according to the degree of lignification of shoots and the accumulation of cryoprotectors. An assessment of their possible use is given. The dendrometric characteristics of the studied species correspond to those that they form in their natural range. All trees, except horse chestnut and Ginnal maple, retain the life form peculiar to the species. The most winter hardiness is distinguished by extrazonal species and shrubs. From the return of cold weather and frosts in the spring period, the petiolate oak and the common ash suffer. In all studied species, except horse chestnut, annual shoots become woody by the beginning of autumn frosts, as a result of which frosts in the prewinter period damage the shoots to a lesser extent. The content of starch and sugars in plant cells prevents the formation of ice crystals in them and damage to cell walls. For the studied species, the average and high sugar content in wood was established. The calculation of the acclimatization number and acclimatization ability largely depends on the hardiness of the plant. The studied dendroflora has a complete and good adaptation to the conditions of the northern agglomeration. In general, the species considered in the study can be recommended for inclusion in the green spaces of the cities of the region and their green zones.