[Wikipedia] Ecology: This plant is a weedy species that favors disturbed environments.[13][14] It has been introduced and become established on all continents except Antarctica.[15] The seeds of the plant are important food for birds,[16] including American goldfinch, Northern bobwhite, and mourning dove, and it is a larval host for both the primrose moth and the white-lined sphinx moth.[17] Bumblebees and honeybees also visit the flowers.[13] The primrose moth (Schinia florida) is a common consumer of Oenothera biennis. The adults lay eggs on the flower, and the emerging caterpillars feed on the plant. Pink wing tips reveal Schinia florida in the flower of the evening primrose. Pink wing tips reveal Schinia florida in the flower of the evening primrose. Primrose moth, Schinia florida, on an evening primrose, petals have been removed to reveal the insect. Primrose moth, Schinia florida, on an evening primrose, petals have been removed to reveal the insect. The seeds of O. biennis can remain viable in the soil seed bank for 70 years or more. (link added by Mary Ann Machi)