Western natives related to and much resembling evening primrose (Oenothera), with bright yellow, four-petaled flowers over a long summer bloom period. Plants are 1–2 ft. tall. In Zone 13, flowering declines in summer heat, and plants flower in spring and from late summer to fall. Plants spread by rhizomes and are useful for summer color in difficult climates. Shear just before spring growth begins. Plant in well-drained soil. They tolerate regular water if drainage is superb.Calylophus drummondianus
Grows to 1 1/2 ft. high, 2 ft. wide, with narrow, tooth-edged, somewhat drooping leaves and inch-wide flowers. This species blooms for a longer period than C. hartwegii in spring, but it does not rebloom as well in fall.
Native to Europe. Coarse, rather weedy garden plant to 3 ft. tall and 2 ft. wide, with finely divided,...
Native to southern Europe. Upright plants grow to 1–5 ft. tall and 1 ft. wide, with deeply cut, ...
An attractive weed of roadsides and grain fields, this Mediterranean species has naturalized in North ...