Plants are important elements of open-green areas in the urban space and perception of an environment. Some plants have seasonal colour changes. The identification of these changes and clarification of the effects on people are quite important for landscape architecture. Seasonal changes of plants in some open-green areas in Duzce were examined in order to explain how it affects people regarding changes in perceptional preferences. Delphi Method was used on photographs as a mean of identification of the visual effects of the plant compositions. The plant composition photographs, which had been examined before, were used in the questionnaire to 370 student groups.