Can You Grow Primrose in California?

California Zones

• California encompasses 11 different USDA plant hardiness zones, from 5a to 11b. This means that average annual minimum temperatures run the gamut from minus 20 degrees Fahrenheit to 45 degrees Fahrenheit. Generally the cooler zones, 5a to 7b, lie inland, to the east and north, closer to the Nevada and Oregon borders. Much of coastal northern and southern California lies in the warmer USDA zones 8a through 10a. There are few primroses that can survive in all of California's plant hardiness zones, but many plants that can survive in most of them.

Widest Range

• Hardy in USDA zones 7 through 9, English primroses (Primula (polyanthus type)) can be grown in parts of northern and southern California. These primroses are brightly colored and available in every shade. At 6 to 12 inches tall, they bloom repeatedly during the growing season, pausing to rest during the hot summer months. Tall Japanese primroses (Primula japonica), hardy in USDA zones 4 through 8, are candelabra types that grow to18 inches tall. They are early-summer bloomers with red flowers.

Warm Zone Choices

• Though the majority of primroses are only hardy to about USDA zone 8b, some will flourish in warmer areas. German primrose (Primula obconica) is hardy in USDA zones 10 through 12 and grows between 9 and 16 inches tall. The white or purple flowers are borne in umbels or flat-topped clusters in late winter or early spring and the leaves are evergreen. At 18 inches tall, Kew primrose (Primula kewensis) is a hybrid, hardy in USDA zones 9 through 11. Its flowers, borne in whorls, are fragrant and bright yellow.

Culture

• Aside from those specimens that are grown strictly as greenhouse plants, primroses grown in California and elsewhere are generally happiest in partial shade with consistently moist soil. Too much sun will cause the leaves to turn brown at the tips and start to curl. If this occurs, move the plant to a shadier location right away. Good drainage is essential, so add grit or other drainage material to the soil when planting. Polyanthus type primroses and some other types will rebloom more quickly if they are deadheaded. This also produces a neater appearance in all species.