Biomorphological characteristics of some species of the genus Spiraea L. in culture in the European Northeast (Republic of Komi)

The study of biology peculiarities of nine Spiraea species under cultivation in the middle-taiga subzone of the Republic of Komi showed that their seasonal rhythm of development matches the climatic conditions of the introduction region. The studied species start to vegetate in the early to mid-May and finish in late September-early October. Plants have high winter hardiness (I and II points), which is due to the early termination of shoot growth in mid- to late July, and their timely lignification.It is noted that cultivated species of the genus Spiraea in the Botanical garden have annual bloom, various species differ in the timing and duration of flowering, size, shape and color of inflorescences. Fruiting of plants is regular, with the formation of high-grade seeds. Most species show high seed germination, continuing at least for two years, from 68% to 91%. It is also shown that in the second year of storage, seed germination increased on average by 7-8%. Biomorphological features of seeds of species of the genus Spiraea L. indicate the possibility of seed propagation and characterize the high degree of adaptation of plants to the climatic conditions of the North.All the above mentioned characteristics such as seasonal rhythm of development, high winter hardiness, decorative qualities, indicators of flowering and fruiting allow to recommend the investigated species of the genus Spiraea for use in ornamental horticulture of the Northern region.