This study contains findings of research carried out at the Botanical Garden of Petrozavodsk State University
(South Karelia, central taiga subzone) in April – October in the period from 1986 to 2012. The subjects of the
studies were introduced plants of three species of Malus Mill.: dwarf apple – Malus baccata (L.) Borkh., wild
apple – Malus sylvestris Mill., and Niedzwetzky’s apple – Malus niedzwetzkyana Dieck. ex Koehne. Phenological
observations were carried out once in 3 days by the N. Bulygin technique (1979). The phenophase
was considered to have occurred if it was observed in at least 30% of the shoots of all specimens of the species
under study. All samples were checked for compliance with the normal probability law. The correlation
coefficients and differences between the mean values were verified to determine their reliability. Elementary
statistics obtained demonstrate, among other things, that the experiment’s accuracy rate is fairly high (4–6%),
while the variation coefficient is small (18–22%). It was found that M. baccata trees begin and end most of
their phenophases approximately 5–10 days earlier than the other studied species. Furthermore, in the beginning
and middle of the growing period, phonological phases of M. baccata proceed at colder weather compared
to the other studied Malus species. At the end of the growing period, these differences among the species
level off. Of all the studied climatic factors, air temperature has the most measurable positive influence on the
development of Malus species in Karelia. Daily average air humidity and precipitation have a less prominent
influence on еру phenophases of the studied Malus species. The course and strength of such influence depend
on the peculiarities of the phenophase itself. All the studied introduced Malus species show a high degree of
introduction prospect (82−93 points) and can be successfully used in Karelia for gardening and landscaping
purposes.