Effects of annual mechanical summer shearing on growth and productivity of six European plum cultivars (Prunus domestica L.) were studied. The cultivars were grown for 15 years on three clonal plum rootstocks and trained to modified leader system. The annual summer shearing reduced growth, yield, and yield efficiency index but did not affect mean fruit weight compared to the trees dormant-pruned annually and trained to modified leader system. Trees that were annually dormant-pruned from 1974 to 1984 yielded similarly when grown on ‘Brompton’ (P. domestica L.) and ‘St. Julien A’ (P. insititia Bailey) and ‘Myrobalan B’ (P. cerasifera Ehrh.). Yields of ‘Verity’ and ‘Valor’ were higher than ‘Iroquois’ and ‘Italian’, which had the lowest cumulative yield. ‘Bluebell’, ‘Stanley’, and ‘Valor’ had intermediate yields. Mean fruit weight was the same for all rootstocks trained to modified leader systems, but, after 7 consecutive years of shearing, pooled mean fruit weight from trees on ‘Myrobalan B’ was smaller than that of other roots. Trees with ‘Myrobalan B’ root were larger than trees grown on ‘Brompton’ and ‘St. Julien A’.