Sandy roadsides, fields, and railroads; plains and dry savanna (oak, sassafras), generally in sunny somewhat disturbed areas with bare, sandy soils.

Oenothera clelandii was segregated from O. rhombipetala in 1983 and differs in having smaller flowers with the stigma at the same level as the anthers. In this species (and presumably also O. rhombipetata), the rosette leaves are pinnatifid, at least on vigorous rosettes, while in the O. biennis complex (O. biennis, O. glazioviana, O. oakesiana, O. parviflora, and O. villosa) rosette leaves are to entire to undulate-margined.