Dwarf Evening Primrose is also known as Missouri Evening Primrose. This tap-rooted perennial produces large, clear yellow flowers that stay open only one day. Plants, however, have a long bloom time, from mid-June through August. Plants are native to the southern and central United States and typically found in poor soils on prairies, cliffs, hillsides, and slopes. Full to partial sun and well-drained soils with dry conditions are preferred.