The calendar of Spiraea flowering in the Mari El Republic

Spiraea are beautifully flowering shrubs that are valued for their high decorative value, a variety of bush shapes and flower colors, abundant flowering, unpretentiousness and high resistance. The exact dates of flowering may vary depending on the climatic conditions of region, so the study of flowering periods in a particular region of introduction is relevant. The purpose of the study was to determine the flowering dates of the species Spiraea in the Botanical Garden-Institute of the Volga State University of Technology (Yoshkar-Ola, Mari El Republic). The observations were carried out in 2023. The objects of the study were 56 species and varieties in the exhibition "Fruticetum". The duration of flowering was 3 months – from May 6 to August 5. In the period up to mid–June, mainly plants with white flowers bloomed, and only 2 species with pink ones – S. Billardii and S. Densiflora. Since the second half of June, the flowering of pink-colored Spireas has prevailed. The distribution of the studied Spiraea into groups with early, medium and late onset and end of flowering has been carried out. A flowering calendar has been compiled. The species S. corymbosa had the longest flowering (56 days), also long-bloomed S. Rubella, S. Latifolia, S. Bumalda and its cultivar 'Antony Waterer', S. Salicifolia and its cultivar 'Alba', S. Humilis, S. Lemoinei, S. Syringaeflora, S. Rosthornii. The data obtained are of value to specialists in the field of landscaping. A limited number of Spiraea species are used in the plantations of settlements of the Mari El Republic, and thanks to the extensive collection of Botanical Garden-Institute, it is possible to enrich the range of Spiraea in urban plantings.

spiraea, blossom, phenological observations, landscaping, ornamental shrubs, duration of flowering, flowering dates, introduction of plants, exposition, botanical garden