Investigations were carried out to find whether enhanced ultraviolet radiation influences the Taxus, Thuja and Juniperus genera used in garden architecture. Seedlings a few years old were subjected to UV-B at a 16 kJ m^-2 day^-1 dose for several weeks. Carbohydrate contents (monosaccharides and sucrose), levels of chlorophylls and chlorophyll a fluorescence were analyzed, and the variable/maximal fluorescence (F_v/F_m) and the Rf_d– vitality index were calculated. In Taxus and Juniperus no negative effects were found in carbohydrate accumulation and even increased chlorophyll a and b levels were noted. After 6-9 weeks of irradiation the amount of these pigments in Juniperus needles was as many as twofold higher. Under the in fluence of UV-B a 50% reduction of monosaccharide accumulation was found only in Thuja, after 3 weeks irradiation, and an approx. 30% reduction in chlorophylls after 6-9 weeks of irradiation. no changes in the F_v/F_m parameter were found in either species, but the vitality index (Rf_d) under the first weeks of radiation stress showed even an increase in Thuja leaves. These results indicate that shoot blight of conifers is not caused by enhanced UV-B radiation.