Leaves are essential in the propagation of roses by cuttings. However, about the underlying principles, there is no unequivocal opinion in the literature. We investigated the hypothesis that current photosynthesis would represent the dominating factor. To validate this hypothesis variations in photosynthesis were created by reducing leaf area, covering of leaves and by reducing CO2 air concentration. The consequences in terms of survival percentage, root formation, and carbohydrate concentrations were followed throughout the first 3 weeks of propagation. Moreover, the known promoting effect of auxins was studied in a comparative experiment to investigate potential auxin deficiencies created by the leaf treatments. Leaf removal, leaf covering or CO2 depletion had a quantitative negative effect on survival and growth of cuttings. Auxins did not promote rooting when leaves were covered or removed. Dry matter distributed uniformly by the leaf and stem of cuttings after 21 days of propagation. Unexpected, and perhaps contradictory, was that, although current leaf photosynthesis seemed the limiting factor for propagation, the majority of photosynthates was stored as starch. This apparent ineffective use of photosynthates could be explained in terms of competition within different sinks. The weak sink of starch accumulating organelles becomes the major sink relatively to the modest sink activity of the new roots and new shoots. In fact, the new formed organs accounted for less than 15␘f the total dry weight of cuttings. It is concluded that photosynthetic capacity of cuttings is to be considered an important determinant for quality in rose propagation. Further research should confirm the relationship between photosynthesis and its value as criterion for quality in rose propagation.