Biological and Morphological Characteristics of Species of the Genus Crataegus L. in the Arboretum of Khakass

In the flora of Khakassia, there is one species of hawthorn – Crataegus sanguinea Pall., its fruits are used as medicinal raw materials. It does not form large thickets, while the raw material is in high demand. Therefore, the introduction of new species of hawthorn is relevant. The aim of the research has been to establish the rhythm of development of the arboretum hawthorns in modern conditions, as well as to identify promising species for use in landscaping in the steppe zone of Khakassia. The hawthorn collection in the arboretum of the Research Institute of Agricultural Problems of Khakassia includes 21 species. Of these, 42.8 % are of North American origin, 19.1 % of species are from the Far East and Central Asia, 9.4 % are from Europe, and 4.8 % are from East Asia. The average age of the plants has been 40.6± ±1.3 years. This age is considerable for the conditions of the dry steppe. Based on statistical processing of phenological data over the past 10 years, the rhythm of growth and development of the hawthorn collection has been determined. The periods of vegetation, flowering, fruiting and leaf fall have been established. The sums of effective temperatures required in the spring-summer period of plant development have been determined. A calendar of hawthorn flowering has been compiled. Most species of North American and all of Central Asian origin bloom at the same time. 42.8 % of hawthorns have been identified, which, in terms of the timing of the stages of vegetation, fully fit into the period for local plants, 57.2 % have a long vegetation period. The peak flowering of the arboretum’s hawthorns falls on May 19–28, with an average flowering period of 9 days. As a result, all the species under consideration are quite promising for cultivation in the conditions of the steppe zone of Khakassia. 28.5 % of species are vegetatively mobile, while the rest are characterized by seed reproduction. Species such as Crataegus songarica C. Koch. and C. arnoldiana Sarg., with fruits of good taste quality, are proposed for use in fruit gardening. Species with spreading crowns can be distributed as solitaires in landscaping settlements in the steppe zone of Khakassia. Drought-resistant hawthorns are suitable for creating tall hedges.