A brief description of three North-American species of rowan trees from the collection of the South-Ural Botanical Garden-Institute of Ufa Federal Research Centre of Russian Academy of Sciences (UFRC RAS): Sorbus decora, Sorbus americana and Sorbus scopulina is given. The climatic conditions of introduction area are similar in temperature to the parameters of the natural range of the North American S. decora: they are not optimal for it, but the plants bloom and give viable seeds. It can be assumed that vital signs of S. decora would be higher in milder climate and favorable water-physical soil conditions. According to the analysis of variance, it is revealed that the conditions of the year and species characteristics significantly affect all the phenological phases of development of North American rowan trees. At the same time, they are more dependent on the temperature conditions of the year (F=17.4 at p<0.001) and less on species characteristics (F=6.2, at p<0.001), although the sequence of phenophases is maintained from year to year. The average vegetation period of rowan trees is 154–163 days. S. decora growing in the Botanical Garden for a long time (planted in 1960–1974) and relatively new species for the collection – S. mericana and S. scopulina (2009–2013) can be considered promising decorative crops for growing in the climatic conditions of Ufa and the Bashkir Urals
NORTH-AMERICAN SPECIES OF ROWAN TREES FROM THE COLLECTION OF THE SOUTH-URAL BOTANICAL GARDEN
