Oenothera biennis (Onagraceae) - Not related to roses or primroses, it gets its name because its flowers open late in the day. This is because it is pollinated by night flying insects. I read that Japanese beetles like this plant, and can be found congregating in it's flowers late in the day. If you wish to rid your garden of theses pests, you can conveniently collect them from this plant and dispose of them... It has a long history of food (the root) and medicinal use from Native Americans to the present day. Nowadays it is often found as an herbal supplement for symptoms of PMS. Other medicinal uses include treatment of alchoholism, eczema ond other skin problems, asthma, and obesity. Common Evening Primrose blooms in summer.
(Photographed in PA)