Assessment of Vitality and Ornamental Quality of Hydrangea paniculata Siebold Cultivars under Urban Conditions of the Volga Region

Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, Moscow, 127550, Russia

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Abstract

Ten cultivare of Hydrangea paniculata Siebold were investigated in Saratov, Russia, over three growing seasons (2022-2024). Plant vitality was assessed using Nikolaevskiy's methodology based on four morphological indicators, yielding an integrated vitality score. Ornamental quality was evaluated according to Fedin's methodology across eleven criteria, including inflorescence colour, flowering duration, fragrance, and winter hardiness. Specimens were examined at ten urban green space types, representing varying levels of anthropogenic stress. Seventy percent of the plants demonstrated excellent vitality (39-40 points), classified as "no signs of decline". Four-cultivars - 'Pinky Winky', 'Summer Love', 'Limelight', and 'Bobo' - were identified as highly ornamental (80-85 points) and resilient under local conditions. 'Skyfall' and ' Strawberry Blossom' exhibited reduced winter hardiness, with >50% dieback of annual shoots. The study established science-based recommendations for selecting H. paniculata cultivars suitable for sustainable urban -greening in the Volga region.