Growing macadamia in zone 10b

Without a defined cold period to synchronize flowering, macadamia in zone 10b can produce racemes of small white to pale pink flowers in multiple flushes across the year. The primary bloom typically runs late winter into early spring, with secondary flushes possible in fall. Nut development from pollination to maturity takes approximately 7 to 9 months, placing the main harvest window between late summer and early winter, though off-season nuts can be present at other times.

Zone 10b's minimum temperatures pose no meaningful frost risk to bloom. The practical harvest challenge is managing multiple ripening cohorts on the tree simultaneously. Nuts are ready when they drop naturally or when the green outer husk begins to split at the seam; calendar date alone is not a reliable harvest indicator in a climate with staggered flowering.

Macadamia in zone 10b needs no winter cold protection, but growers should build their management program around two zone-specific pressures. First, sooty mold is the principal disease threat in sustained tropical conditions. It develops on honeydew deposited by scale insects and aphids rather than from primary infection, so controlling the insect vectors through horticultural oil applications is more effective than treating the mold surface directly.

Second, coastal sites with saltwater intrusion require periodic soil monitoring for chloride accumulation. Macadamia is moderately sensitive to elevated soil salinity; deep irrigation every few weeks during dry periods helps leach salts below the active root zone. Heavy organic mulch around the trunk conserves soil moisture and moderates temperature swings during any dry season. Irrigation consistency matters more in zone 10b than in cooler parts of the crop's range because the trees have no seasonal dormancy period to buffer moisture stress.