Like other Coreopsis species, Prairie Coreopsis has abundant yellow blooms. The bloom period lasts from late May through July. Deadheading spent flower stalks can extend bloom time as well as prevent unwanted self-seeding. This plant has attra ... ctive, finely textured foliage that stays green through summer and fall, usually until the first hard frost. It will spread by rhizomes, forming small, attractive colonies with excellent flower displays.