California desert bluebells (Phacelia campanularia). Bell-shaped, dark blue flowers; gray-green, coarse-toothed leaves. Grows 6 to 18 inches tall and wide. Sunset climate zones 1-3, 7-24.
California poppy (Eschscholzia californica). Satin-textured, single-petaled flowers, pale yellow to deep orange, on stems 8 to 24 inches long. Zones 1-24; H1.
Corn cockle (Agrostemma githago). Mauve-purple flowers with darker veins. Grows 2 to 3 feet tall and 1 foot wide. Good for cutting. Zones 1-24.
Desert marigold (Baileya multiradiata). Inch-wide, bright yellow flowers; gray-green foliage. Grows 1 to 1 1/2 feet tall. Native to Western deserts. Zones 1-3, 7-23.
Godetia (Clarkia amoena). Single or double flowers in lilac to reddish pink and blotched or streaked with crimson. Grows 18 to 30 inches tall. Good cut flower. Zones 1-24.
Honeywort (Cerinthe major). Upper stems bear sprays of nodding, tubular, violet-blue flowers; fleshy stems and leaves. Grows 2 feet tall and as wide. Attracts bees. Zones 1-24.
Larkspur (Consolida ajacis). Blossom spikes densely set with flowers in shades of white, blue, lilac, and pink above finely cut, ferny leaves. Grows 1 to 4 feet tall. Zones 1-24.
Love-in-a-mist (Nigella damascena). Blue, rose, or white spurred flowers, followed by attractive seedpods (useful in dried arrangements). Grows 1 to 1 1/2 feet tall. All zones.
Shirley poppy (Papaver rhoeas). Single or double cup-shaped flowers in shades of red, pink, orange, and white, including bicolors. Grows 3 feet tall. Zones A1-A3; 1-24 (best in cool-summer areas).
Sweet alyssum (Lobularia maritima). Clusters of tiny, four-petaled white flowers on low mounds that grow 1 foot tall and wide. In mild climates, blooms nearly year-round from self-sown seedlings. Attracts bees. All zones.