Pink evening primrose (Oenothera speciosa).
Pink evening primrose features fragrant, bowl-shaped, four-petaled, pink flowers (to 2-3" diameter) with yellow anthers that bloom from the upper leaf axils in late spring. Pink ladies or Pink evening primrose is an upright to sprawling, 1 1/2 ft. perennial, which spreads to form extensive colonies. Cold hardy in USDA zone 5-8.
If you want more information about this flower, just search the plant's Latin (botanical) name on Google: