If plants in your California garden yellow and die no matter how well you care for them, you may have acidic soil. Soil is considered "acidic" if it has a pH (potential Hydrogen) measurement of less than 7.0, which is considered "neutral," with soil that has a measure 8.0 to 14 is alkaline. Fortunately, according to the Las Pilitas Nursery, in Escondido and Santa Margarita, it is possible to have a beautiful garden if you test your soil's pH, then use plant varieties best adapted to your acid soil.
California is in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 5a to 11, with the majority of the state in zone 9. Gardeners are advised to determine their specific zone and check plant requirements before using any of these zone 9 acid-loving plants in their California gardens.
Jungle flame (Ixora coccinea) is from the madder family and is an evergreen shrub that can also be known as ixora or flame-of-the-words. It will grow 4 to 6 feet tall on average or up to 12 feet tall. Leaves are leathery and oblong, 4 inches long. Flowers are red and tubular, on clusters 2 to 5 inches wide. Colors for the blooms are usually yellow, orange or pink. Plant this in acidic soil with good mulch in a partial-shade location. Propagate via tip cuttings and grow in USDA hardiness zones of 9 to 11.
Chapman's azalea (Rhododendron chapmanii) is from the dogbane family and is an evergreen shrub that is also known as Chapman's rhododendron. It will get 4 to 10 feet tall and the same in width. Leaves are dark green and leathery, 1 to 2 inches long. Flowers are rosy pink and funnel shaped, 2 inches wide in clusters. Plant this one in filtered sunlight in moist acidic soil. Propagate via tip cuttings or seed in USDA hardiness zones of 7 to 9.
Bald-cypress (Taxodium distichum) is from the bald-cypress family and is a fast-growing tree that is drought resistant. It can get 130 feet tall with reddish gray or brown bark and deciduous needle leaves. Cones will produce in summer and be 1 inch wide. Plant this one in acidic soil in full sun locations. Propagate via seed and grow in USDA hardiness zones of 5 to 10. The tree's preferred pH range is undefined but it will yellow if not in acidic soil.
Stoke's aster (Stokesia laevis) is from the aster/daisy family and is an evergreen easy to grow perennial. It has 6 to 8 inch leaves with flowers like cornflowers that are 3 to 4 inches wide. Stems are 1 to 2 feet tall. Colors can be dependant on the cultivar, in the hues of white, pink, blue or lavender. Plant this in acidic soil in full sun. Propagate via root-clump division or seed and grow in USDA hardiness zones of 5 to 10 in soil with pH of 5.5 to 7.5.