Growth retardants may affect some morphological and physiological traits of plants. The aim of the research was to evaluate the influence of a single, flurprimidol spray on transpiration, growth and flowering of geranium. Flurprimidol (Topflor 015 SL) was applied once, as a foliar spray at 7.5, 15.0 or 22.5 mg dm(-3). The desirable heights of 'Classic Noblesse' and 'Classic Diabolo' geraniums were obtained with flurprimidol at concentrations of 22.5 and 15.0 mg dm(-3), respectively. Flurprimidol had no influence on stomatal conductance, transpiration rate, the number of days to flower, diminished plant diameter, leaf area, plant fresh and dry mass, inflorescence area index, inflorescence number and increased the inflorescence area to plant height ratio. Chemical name used: alpha-(1-methylethyl)-alpha-[4-(trifluromethoxy)phenyl]-5-pyrimidinemethanol (flurprimidol).