The effect of BA on the flowering of Campanula persicifolia L. ‘Alba’ cultivated in an unheated plastic tunnel and in the field was examined. BA in the concentration of 100, 200, 400 mg∙dm^-3 was applied on the leaf twice in both years of the experiment duration. Plants not treated with benzyladenine were used as a control. It was concluded, that cultivation of Campanula persicifolia L. ‘Alba’ in an unheated plastic tunnel causes growth of fewer inflorescence stems but of better quality than in the field. Application of benzyladenine in the concentration of 400 mg∙dm^-3 in Campanula persicifolia L. cultivation in an unheated plastic tunnel results in an increased fresh weight of inflorescence stems and number of primary side stems. Application of benzyladenine in the concentration of 400 mg∙dm^-3 is recommended for Campanula persicifolia L. cultivated in the field due to better branching in the first and second year of flowering. Application of benzyladenine in the concentration of 200 and 400 mg∙dm^-3 on the leaf of Campanula persicifolia L. cultivated in the tunnel leads to the production of shorter inflorescence stems in the first and second year of flowering. In the field, only the older plants (in the second year of flowering) react similarly.

57-63