Experimental data for 2017-2020 are presented. The influence of microbiological preparations produced in the biological laboratory of the Federal State Institution “Omsk Reference Center of Rosselkhoznadzor” on the reproduction of introduced tree species growing on the territory of the natural monument of regional significance “Regional Dendrological Garden named after G.I. Gense” is analyzed. Reproduction of tree species was carried out using lignified (winter) cuttings in open ground conditions. Microbiological preparations were used based on Pseudomonas aureofaciens (Elena), Azotobacter vinelandii (Azolene), Trihoderma viride (Trichodermin) and Exophiala Nigrum (Black yeast). Their positive effect on rooting, development of the root system, an increase in the diameter of the root neck and growth in annual, biennial, three-year and four-year seedlings was established. The best preparations that influence the formation of more vigorous seedlings with the most developed root system are Black yeast and Trichodermin. The tree species that was more responsive to the use of the studied microbiological preparations was the spherical willow (Salix fragilis).