Decorative effect of the genus Spiraea L. species during introduction in the south of the Primorsky region

The purpose of the study is a comprehensive assessment of the decorative properties of Spiraea L. species when introduced in the south of the Primorsky Region, the results of which can be used for planning green building facilities. The study was carried out on the basis of collections of species and varieties of spirea from the arboretum of the Gornotaezhnaya Station of the Far East Branch of the Russian Academy of Sciences, which has been formed for more than 30 years and is stable in the difficult climatic conditions of the Southern Primorye. On the basis of a widely used methodology, a scale for a comprehensive assessment of the decorative effect of species and varieties of spirea was developed. The gradation of decorative properties of richness presented in the rating scale is their diversity in various species and varieties of spirea, which provides great opportunities for creating highly artistic garden and park compositions. Currently, in the collection of spireas, one taxon (S. × vanhouttei) belongs to the group of highly decorative (80-100 points), 11 species and sorts are included in the group of ornamental (50-77 points), 5 are low decorative species (45-49 points). The group of low-decorative plants with poor resistance to powdery mildew diseases and reduced abundance of flowering (single inflorescences) includes possible species: S. betulifolia, S. chamaedryfolia, S. elegans, S. flexuosa and S. sericea. The highest decorative effect was noted in S. japonica varieties, which are distinguished by bright multi-colored leaves, as well as in hybrid spirea S. × cinerea Grefsheim and S. × vanhouttei with snow-white numerous inflorescences and graceful weeping shoots. Types of spirea from the groups of highly decorative and decorative are recommended for widespread use in landscape design and landscaping of residential areas.