Formation of the <i>Astilbe</i> Buch.-Ham collection in a continental climate

The paper analyzes the dynamics of formation of a collection of Astilbe varieties and species included in the bioresource collection USU 44053 in the conditions of Western Siberia forest-steppe. The ways of further expansion of Astilbe collection fund are substantiated by attracting representatives of the Astilbe chinensis, A. crispa groups; varieties with rhombic, narrow-lobed and pyramidal inflorescences, primarily belonging to the group of colors: red, dark red, purple and dark purple. In contrast to the conditions of the middle zone of Russia in which Astilbe are divided into four groups according to the period of flowering: 1) very early (end of June July), 2) early (July), 3) medium (mid-July mid-August) and 4) late (end of August mid-September), for the conditions of Western Siberia forest-steppe, with intense heat gain in mid-May-early June, the flowering dates of very early and early varieties converge. Accordingly, there are three groups: early-flowering (bloom July 810), medium-flowering (bloom from July 1518), late-flowering (bloom from late Julyearly August). It is proposed to add a narrow-lobed and pyramidal-drooping inflorescence to the traditionally described forms of Astilbe varieties. The expansion of the set of dwarf varieties from the A. crispa group with strongly dissected fringed leaves gives additional opportunities for a landscape design.