Factors affecting the rooting of plum hardwood cuttings

Optimum conditions for rooting hardwood cuttings of several plum rootstocks have been determined with respect to season of cutting collection, the thickness of shoot and the part of the shoot used as the cutting, the concentration of rooting hormone applied to the base of the cutting and the basal temperature in the rooting medium.

Rooting occurred most readily during autumn and again in late winter and spring. Cuttings made from “thin” shoots generally rooted more readily than those from “thick” ones but the position along the shoot from which the cutting was made was usually unimportant.

Some clones, including Myrobalan B and St. Julien A, responded to increasing concentrations of 4(indolyl-3) butyric acid (IBA) to an optimum at 5,000 p.p.m. and to increasing bottom heat to about 20° C. Others, including Brompton and Pershore, were relatively unresponsive to both of these factors under the conditions of these experiments.