Environmental protection imposes strict limitations in using fertilizers and plant protection products. This is why there is a need for research on using plant products in horticultural production. In the experiment conducted in the years 2009–2012 the influence of spraying of maiden pear trees with ERGOPLANT biostimulant was estimated. Growth of ‘Isolda’, ‘Conference’ and ‘Uta’ maiden pear trees budded on two types of quince rootstock S1 and MA was compared. The application of biostimulant ERGOPLANT increased significantly growth of maiden pear trees and their compatibility with the Polish Norm. The examined rootstocks influenced significantly number of roots of maiden pear trees. The biggest diameter and the best quality of maiden pear trees was obtained for ‘Uta’. Maiden leaves of this cultivar had also a higher content of chlorophyll compared with the two remaining cultivars. In cross sections of anatomic connections of ‘Isolda’ or ‘Uta’, with quince rootstocks especially with MA, the presence of a layer of necrotic cells was observed.