Floral color change has been suggested to benefit plants by manipulating pollinators, but this trait appears hardly prevalent among angiosperms. One possible explanation for this discrepancy is that color changing plants may have responded to distinct selection pressures imposed by their own pollinators. We therefore compared pollination process between two species in Weigela; W. coraeensis (W. c.) change floral colors from white to red-purple, while W. hortensis (W. h.) flowers remain pink. However, both species did not differ in floral longevity and produced less nectar in old flowers. Pollinators discriminated young, high-rewarding flowers by colors on W. c., while they did not do so on W. h. This suggests that pollinators foraged more efficiently on W. c. plants. W. c. flowers received more pollinator visits and pollens than W. h., because bees strongly preferred W. c. As a result, proportion of seed set in W. c. reached 95%, while it was limited to lower levels in W. h. Considering that only W. c. provided color cue for choosing high-rewarding flowers, it is likely that bees—known as cognitively sophisticated insects—learned to make more returns to W. c. plants. Results indicate that floral color change benefits plants when they could improve pollination by motivating bees to return. However, this trait would be too costly in habitats with no good prospect for increased returns by bees.