Regulating Poinsettia's Height (IMAGE) American Society for Horticultural Science Caption A study determined that application of controlled water deficit can be effective as a means to regulate stem elongation in poinsettia, and that water deficit suppresses poinsettia stem elongation by reducing the length of the shoot internodes. Credit Photo courtesy of Peter Alem Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.