Hardiness zones:
Sunset 10-24
USDA 9-11 (arid regions best)

Landscape Use: Xeric accent shrub, strong attractant of hummingbirds which are very territorial about this plant, also attracts bees.

Form & Character: Evergreen shrub, open stiff to graceful, INFORMAL (don't shear), C. californica is typically more luxuriant and vigorously upright than C. eriophylla though hybridization and the resultant genetic mixing of these two landscape plant taxa within the Phoenix urban environment has muddled this.

Growth Habit: One form is upright from base to 4-8' while another form is coarse branching and spreading to only 2-3'.

Foliage/texture: Small pinnately-compound leaves, leaves close during night, fine texture

Flowers & fruits: Numerous brilliant red pin cushion flowers in terminal and auxiliary clusters followed by erect to upright pubescent pods to 3" long

Seasonal color: Sometimes spectacular displays of red flowers during the entire year except summer, most prevalent in November to March.

Temperature: Tolerant

Light: Full sun

Soil: Tolerant of most Arizona soils, though well-drained drier soils are best. Foliar chlorosis or leaf yellowing is common nutritional disorder if soils are chronically wet.

Watering: Apply infrequent and deep supplemental watering during extended dry periods only for best appearance. Irrigations will also increase overall plant vigor and eventual size. Do not excessively water as this will promote rank growth. Both California and Baja fairy duster plants are prone to lose leaves (drought deciduous habit) during extended periods of dry soil conditions - don't freak out, this is okay. 

Pruning: Don't regular shear of hedge, rather head back lightly to severely as necessary in early summer.

Propagation: Acid scarification of seed in order to seed propagate, otherwise vegetative cutting (use a perlite based medium) is more difficult.

Disease and pests: None

Additional comments: California fairy duster is a tremendous addition to any xeric landscape design. Calliandra californica and eriophylla will readily hybridize. This makes urban seed collection interesting because progeny (seed produced offspring) are just as likely to have a mixed up array of pink and/or red flower colors and a range of growth habits from prostrate to stiffly upright. 'Sarita' is a cultivar of  C. californica with a profoundly prostrate habit that was found and patented by a former graduate student of mine named Sarah Celestian. Natural reseeding of Calliandra species in the Phoenix urban environment is common and is stimulated around points of irrigation or in areas mulched with gravel (enhanced seed scarification).