Abstract
The article discusses the growth and development of introduced species and cultivars of the Spiraea genus in the collection plantings of the dendrological park, arboretum, and new cultivars in the nurseries of the A.N. Bukeikhan Kazakh Research Institute of Forestry and Agroforestry. Fourteen species and varieties of ornamental shrubs from this genus are being tested at the plant introduction sites. The article provides a brief description of the long-term climatic conditions of the study area and the duration of the growing season. The climate of Northern Kazakhstan is sharp continental, and is characterized by low winter and high summer temperatures, late spring and early autumn frosts, and low precipitation. The article provides data on the morphological parameters, the beginning and duration of flowering of some species and cultivars of Spiraea. The new Spirea varieties, along with previously cultivated ones, demonstrated high resistance to adverse weather conditions. Two new varieties, 'Dart's Red' and 'Anthony Waterer,' have reported their first flowering. It also provides a comparative analysis of our research with the available literature on the flowering and growth of Spiraea cultivars. The article identifies groups of shrubs based on their height and current growth. The Spirea species and varieties studied were generally characterized by medium to short stature, compared to published data. The article provides recommendations for the use of Spiraea cultivars in various plantings in Northern Kazakhstan.