Because Common Evening-primrose (Oenothera biennis) is a biennial, in late summer it is possible to find first-year leafy rosettes growing near tall second-year flowering plants. Just as with Wild Carrot, it's the first-year plants that provide a tasty taproot to knowledgeable foragers. The taproots can be gathered from late summer through spring (so long as the ground is not frozen) -- they go out of season when the plant begins to produce an aerial shoot (which also happens to be edible). Given the number of vegetables Common Evening-primrose provides (flowers, buds, taproots, shoots, etc.), she is well worth befriending.