The present invention provides a composition capable of regulating growth of a plant or propagation material thereof comprising as plant growth regulating active ingredient a mixture of component (A) and component (B) wherein component (A) is Paclobutrazole and component (B) is selected from the group consisting of Difenoconazole, Ipconazole, Metconazole, Tebuconazole, Prothioconazole, Cyproconazole, Propiconazole and Epoxiconazole wherein component (A) and component (B) are present in said composition in amounts which produce a synergistic effect. Preferably the composition comprises Paclobutrazole and Difenoconazole and the composition inhibits growth of the plant upon application thereby increasing yield/quality. The compositions are also capable of preventing and/or treating growth and/or infestation of phytopathogenic fungion a plant or propagation material thereof.