Ecological and biological features of annual ornamental plants under pre-winter sowing in a continental climate

The paper presents the results of a long-term study of biological features of annual ornamental plants species belonging to the ecological group of therophytes included in the bioresource collection USU 44053 and capable of creating a high ornamental effect after pre-winter sowing in the ground. The hydrothermal conditions of the wintering and subsequent vegetation periods are characterized. The accumulation of snow necessary for successful overwintering of seeds is analyzed. Comparative phenospectra of species under different cultivation methods are presented, with an emphasis on achieving the fruiting phase. Examples of naturalization of these species are given, which characterize their high adaptive potential. The most promising species for use in the urbanized environment of the Siberian region are: Amaranthus caudatus L., A. paniculatus L., Brachycome iberidifolia Benth., Calendula officinalis L., Centaurea cyanus L., Clarkia unguiculata Lindl., C. pulchella Pursh., Eschscholzia californica Cham., E. pulchella Cham., Gilia achilleifolia Benth., G. capitata Sims, G. tricolor Benth., Gypsophila elegans M. Bieb., Helichrysum bracteatum (Vent.) Andrews, Iberis umbellata L., Layia elegans Torr. A. Gray, Rudbeckia hirta L., Salpiglossis sinuata Ruiz Pav., Schizanthus pinnatus Ruiz Pav., Vaccaria hispanica (Mill.) Rauschert.