Description:
<jats:p>Plantings’ ornamentality is an important aspect of the aesthetic appearance formation of urbanized landscapes. In urban ecosystems, trees and shrubs are often exposed to high stress levels that shortens their lifespan and reduces ornamentality. Plant introduction is one of the methods of enriching the assortment with resistant species. The aim of the research was to comprehensively assess the ornamentality degree of North American introduction tree groups from the genetic collection of the All-Russian scientific research Institute of Fruit Crop Breeding (VNIISPK) arboretum and to give recommendations on improving their composition. Research was carried out in 2013-2019, taking into account the dynamics of changes in decorative qualities during the year. Throughout the year, landscape compositions showed peaks of ornamentality in the same seasons of the year (May, September). To give dynamism to groups in the summer period, it is recommended to plant Spiraea douglasii in the 1st group; in composition 2 — Hydrangea arborescens and two varieties of Physocarpus opulifolius: ‘Darts Gold’ and ‘Summer Wine’. Graphics of ornamentality degree changes of landscape groups are recommended to be used when drawing up landscape groups for various purposes to ensure their ornamentality during either an entire year or a certain period.</jats:p>