A great number of plant species that are commonly grown in urban green areas can cause health problems due to the formation of allergenic pollen. The management of plants in urban areas often ignores the potential allergenic effect of ornamental plants. In this paper the ornamental trees and bushes in the Ribnjak Park were analyzed to determine their abundance and diversity and to evaluate their potential allergenicity. Plants were also analyzed in view of their adaptation to ecological factors expressed by ecological indicators. There were noted 84 species and one subspecies that were classified in 48 genera and 26 families. There is a total of 11 ornamental taxa represented by varieties, i.e. cultivars, and five hybrids. The most abundant ornamental plants are: Acer campestre, Acer platanoides and Symphoricarpos albus. Potentially, the most allergenic tree is Betula pendula (silver birch) followed by taxa from the families of Aceraceae, Juglandaceae, Fagaceae and Platanaceae. The most allergenic bush is Corylus avellana. The least allergenic tree is Fraxinus angustifolia, and the bush Mahonia aquifolium. This paper aims to contribute to knowledge and understanding of the potential allergenicity of ornamental plants in the Ribnjak Park as well as their adaptation to ecological factors.