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 to 2 ft. tall. In Zone 13, flowering declines in summer heat, and plants flower in spring and from late summer to fall. Spread by rhizomes and are useful for summer color in difficult climates. Shear just before spring growth begins. Plant in well-drained soil. Tolerate regular water if drainage is superb.Calylophus hartwegii
Grows up to 1 ft. high, 2 ft. across, with inch-wide flowers; those of ‘Sierra Sundrop’ are larger. Calylophus hartwegii lavandulifolius (C. lavandulifolius) has narrow, gray leaves. Excellent in hot, dry locations and when mixed with desert perennials.
Native to the dry regions of the Southwest and northward to Canada. Forms a clump 1–2 ft. high and wid...
Native from southern Wyoming to Arizona and New Mexico. To 2–3 ft. tall, 2 ft.wide. Dark green l...
Native to dry regions of the Southwest and northward to Canada. Forms a clump 1-2 ft. tall and wide; t...