The state of planting Rhododendron L. in the phytocenosis of the lower river Kamianka of the Sofiyivka National Dendrological Park of NAS of Ukraine

Abstract

Aims. Assess the state of planting Rhododendron atlanticum (Ashe) Rehd., Rh. viscosum ‘Lollipop’, Rh. obtusum ‘Меlina’, Rh. o. ‘Königstein’, Rh. o. ‘Hino Crimson’, Rh. o. ‘Pure White’, Rh. o. ‘Anuke’, Rh. luteum ‘Soir de Paris’, Rh. l. ‘Corneille’, Rh. l. ‘Tunis’, Rh. l. ‘Jolie Madame’, planted in the phytocoenosis of the lower river Kamianka in the National Dendrological Park “Sofiyivka”, located in the southern part of the Right-Bank Forest-Steppe of Ukraine; to highlight the main factors that influenced the stability of these taxa in the conditions of the studied region. Methods. Field research; assessment of the shrubs' condition was carried out according to the methodological recommendations for taxation of perennial planting in the historical parks of Ukraine. Results. The cultivars Rh. o. ‘Königstein’, Rh. o. ‘Меlina’, Rh. o. ‘Hino Crimson’, Rh. o. ‘Pure White’ during 5 years of cultivation successfully took root and adapted to soil and climatic conditions of phytocenosis, have good condition (Quality Assessment Factor (QA) 1.0–0.7). Other taxa were less resistant and require a higher agrophone for growth: they showed signs of satisfactory and unsatisfactory conditions (QA 0.3–0.7) — underdeveloped crown, slow growth, reduced shoot growth length, presence of dry shoots in the upper tier of the crown, low leafiness, dullness of leaves, reduced number of generative buds. The main factors that adversely affect the survival rate, adaptation process and plant viability were identified. Conclusions. In the lower river Kamianka at the site “Nova Sofiyivka” of the dendrological park “Sofiyivka”, during the five-year period of rhododendron cultivation, four cultivars of Rh. obtusum, except Rh. o. ‘Anuke’ were in good condition and were distinguished by high drought and winter hardiness in the southern part of the Right-Bank Forest-Steppe of Ukraine. Rh. atlanticum, Rh. viscosum ‘Lollipop’ and Rh. luteum cultivars had unsatisfactory and satisfactory conditions: they were less drought-resistant and required higher agrophone to increase resistance.