Species within the genus Helleborus differ in the relative location of their sepals. Previous studies have proved the existence of post‐floral functionality of sepals in H. foetidus , which leads us to consider the possibility of differences in the functionality of the sepals in H. viridis subsp. occidentalis . In this study, we analyzed their influence on the number and weight of seeds through experimental manipulations, which involve a progressive reduction of sepals following fertilization. Our results show that different levels of perianth reduction have no effect on the number and weight of seeds in Helleborus viridis subsp. occidentalis . We propose that differences in the timing of leaf development and changes in the position of floral organs among the different Helleborus species, underlie a distinctive response to the ever‐changing weather conditions of the European winters and springs.