California has five climate zones, according to the USDA Plant Hardiness Zone Map, and though zones 5 to 10 are represented in the state, the most populous areas, along the coast, are zones 8 to 9. Many winter annuals, which provide a splash of color during the coldest time of year, do well in all parts of the state. These plants should be put into the ground in mid to late fall to get the best winter color.
African daisies (Dimorphotheca) are popular in many climates as winter color. These plants are hardy in cool weather and perform particularly well in California's mild winter areas (lower elevations) and can grow to 18 inches. African daisies, which are available mostly in purples and yellows, will close in shade, during overcast times and at night. Dimorphotheca pluvialis is available in apricot, purple, salmon, white and yellow. The popular Glistening White variety is white on top with violet or purple on the underside of the leaves while the Dimorphotheca sinuata variety is yellow-orange on the top of the petals. These plants perform best in full sun with moderate water and may be planted in the fall.
Marigolds (Calendula officinalis) are among the most common of annuals and in California are used in the spring, but also may be planted in the fall to provide a burst of color through the mild winter. Marigolds may be transplanted or started from seed in mid-fall for a winter bloom. The most well-known marigolds have bright orange or yellow blooms, but these plants are also available in cream and softer yellows. Some varieties may grow to 24 inches, but most are much shorter. Often used in mass plantings in public spots like parking lots or medians, marigolds should be deadheaded when blooms are spent. This will promote additional flowering. Marigolds prefer full sun and moderate water.
Pansies (Viola wittrockiana) are technically perennials, but like their cousins, the viola, they are usually planted as annuals. In California, these plants do well in the late winter to early spring and also late fall through the winter. Often used as mass color in borders or as edging, pansies are available in rainbow of colors, including blues, purples, yellows and reds, and some bi-color varieties are also available. Pansies, which may grow to nine inches, may be transplanted or started from seed in mid-fall for winter blooms. These plants prefer full sun and regular water.