Перспективи культивування рослин роду рододендрон (Rhododendron L.) в умовах північної частини Лівобережного Лісостепу України

Abstract

The genus Rhododendron includes more than 1,000 species, a part of them is used in many countries for the ornamental purposes. In contrast, that plant is not widespread in Ukraine, because the peculiarities of its introduction have not been studied sufficiently. Our paper presents the results of the preliminary assessment of the promises for growing rhododendron 30 cultivars and species in the northern part of the Ukraine’s Left-Bank Lisosteppe. The evaluation was carried out on the parameters of winter hardiness, intensity of formation of viable seeds and shoots, and maturation of the latest, preservation of the bushes shape and reproductive efficiency. In the group of evergreen and semi-evergreen plants 67 % of the 15 researched taxa have appeared to belong to the first group of prospects for usage, i.e. almost without restrictions. 5 other taxa have been referred to group II due to the increased are classified to group II, due to increased sensitivity to early spring positive temperatures and subsequent frost damage. This group includes ‘Pearce’s American Beauty’ (Rhododendron catawbiense), ‘Geisha Orange’ (Rh. obtusum), hybrid varieties ‘Erato’ and ‘Rasputin’ and Rhododendron sichotense. In addition, the first two cultivars did not form seeds during the growing season. Among the 15 species and varieties of the studied deciduous plants, only 2 (Rh. mucronulatum, Rh. prinophyllum ‘White Lights’) belong to group II of prospects. A week maturation and increased sensitivity of shoots to the early spring positive temperatures were noted in the first species, whereas in the second species a lack of seeds in the boxes was fired, that is low genitive capacity. In the first species there was a weak maturation of shoots and increased sensitivity to early spring positive temperatures. In the second species there is a lack of seeds in the boxes, i.e. low generative capacity. Regardless of the prospects of rhododendron using in the investigation region, their successful vegetation requires utilizing the modified pH, which includes the sphagnum peat and light composted pine cones and needles (2:1).