Sex Change

Weigela middendorffiana flower color change

Did that get your attention?  It certainly does for the bees that pollinate Weigela middendorffiana.  They have learned to visit yellow flowers preferentially, as they contain the most nectar.  As the flowers age, they turn red, and one study noticed that bees visit the older, less nutritious flowers less frequently.  Floral color change after fertilization is not uncommon (Asters, Orchids, Fuchsias), but the color change is probably dependent on age, not bee-behavior, because the pollen tubes require several days to reach the ovaries.  If the flower dropped off right after pollination, the plant wouldn’t be able to reproduce!  Thanks again go to Dan Hinkley and the Miller Garden for introducing me to this unusual shrub.

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