Characteristic of passaging some phonological phases among <i>Hydrangea</i> L. representatives in the humid subtropics of Russia
Valuable ornamental flowering shrubs are representatives of the genus Hydrangea ( Hydrangea L.), which in recent years have become popular and in demand in landscape construction and phytodesign. However, introduced hydrangeas are not yet widely used in regional landscaping, since their biological features in the climatic conditions of humid subtropics have not been studied enough. In this regard, the aim of the work was to study the phenological phases such as beginning of vegetation and flowering for Hydrangea L. representatives in the humid subtropics of Russia. Based on the phenological observations, hydrangea cultivars were distributed according to the beginning of vegetation into different groups: early ‘Madame Faustin Travouillon’, ‘Joseph Banks’, ‘Mariesii Silver’, for. rosea, ‘Bichon’, ‘Draps Wonder’, ‘General Patton’, ‘Soeur Therese’, ‘Madame Maurice Hamard’, ‘Mariesii Grandiflora’, ‘Mariesii Lilacina’, (from March 13 to March 21), medium ‘Le Cygne’, ‘Mariesii Perfecta’, ‘Monsieur Ghys’, ‘Madame de Vries’, ‘Bouquet Rose’, ‘Generale Vicomtesse de Vibraye’, ‘Mousseline’ (from March 22 to March 31) and late ‘Altona’, ‘Admiration’, ‘Arlequin’, ‘Hamburg’, ‘Popcorn’, ‘Pensee’, ‘Porzellan’, ‘Venus’, ‘Alpengluchen’, ‘Jogosaki’ H. serrata ‘Intermedia’ (from April 1 to April 10). Also, hydrangea cultivars were divided by the dates of the beginning of flowering into groups: early flowering - ‘Altona’, ‘Admiration’, ‘Draps Wonder’, ‘General Patton’, ‘Madame Maurice Hamard’, ‘Madame Faustin Travouillon’, ‘Joseph Banks’, ‘Mariesii Silver’, ‘Soeur Therese’, for. rosea, ‘Mariesii Perfecta’, ‘Jogosaki’, ‘Bouquet Rose’, ‘Generale Vicomtesse de Vibraye’, ‘Monsieur Ghys’, ‘Pensee’, ‘Porzellan’, for. rosea (from late May); medium flowering - ‘Arlequin’, ‘Le Cygne’, ‘Bichon’, ‘Popcorn’, ‘Hamburg’, ‘Mariesii Lilacina’, ‘Venus’ (from early June); late flowering - ‘Mousseline, H. serrata ‘Intermedia’, ‘Alpengluchen’ (from mid-June). The difference between hydrangea cultivars is in the terms of the beginning of vegetation and flowering, as well as is the duration of flowering, which is important in landscape construction to extend the overall flowering period for this