This study was carried out at the Institute of Terrestrial Ecology (ITE), Bush Estate, Scotland, and at the Centre for Tropical Agricultural Research and Education (CATIE), Turrialba, Costa Rica, from December 1989 to September 1993. The work concentrated on two hardwood species native to Central America, Albizia guachapele (Kunth) Dug, and Cordia alliodora (Ruiz & Pavon) Oken. The main objectives of the study were to determine the effects of physiological factors on the rooting ability of both species and identify the optimal conditions for root initiation in leafy, stem cuttings using non-mist propagators. The study focused on some of the factors, both pre- and post-severance, generally accepted as having a crucial influence in determining the rooting ability of leafy cuttings. These included the stockplant growth environment, cutting origin, cutting foliar area, auxins, rooting media and propagation environment. Discussions are presented on the effects of these factors on cutting morphology and physiology, and their influence on the process of adventitious root formation. The practical implications for the propagation of both species and for further research are also discussed.