One of the main cause of relativly slow afforestration with white poplar are problems in rooting of its hardwood cuttings. One way of stimulation of white poplar cuttings’ rooting is treatment with appropriate plant growth regulators, mainly those with auxin effect. In this work the results of the experimental application of powder formulations with indolbutiric acid (auxin) and cobalt chloride (ethylene action inhibitor) in nursery conditions are presented. Beside effect of examined powder formulations, the effect of differences between genotypes (Populus alba cl. Villafranca and cl. L-12) was examined, as well as, for genotype Villafranca, the effect of differences between three nurseries. Obtained results suggest the positive effect of implementation of cobalt chloride in formulations dedicated to the stimulation of white poplar cuttings’ rooting, as well as on differences between genotypes in their reaction on examined formulations. After the treatment of cuttings of Villafranca with combined formulation with 100 μM CoCl2·6H2O and 0.6% indolbutiric acid, beside pozitive effect on cuttings surivival, the positive effect on the rooted cutting height was achieved as well, resulting in signifficantly higher partition of plants apropriate for planting than in control (50-100% higher, depending on nursery). Presented results suggest the significant potential in the implementation of cobalt chloride in white poplar nursery production.