The effects of Mg applications on leaf Mg and yield were studied in a ‘Shamouti’ orange (Citrus sinensis) grove which had exhibited low leaf-Mg concentrations over six years. Soil applications of magnesium chloride were applied with a 35-cm-wide band under the tree canopy or injected into the irrigation system for two successive years, while magnesium nitrate was applied annually as a foliar spray. The band application increased the leaf Mg concentration by 0.2% and raised it to the sufficiency range for three years. One foliar spray, applied annually from the third year onwards, in addition to a soil application, maintained Mg content of the leaves within the optimal range. Average yields and the yield in year six were greater with combined soil and foliar Mg applications than in the unfertilized controls. Once leaf Mg concentrations have fallen to deficiency levels, it takes a long time for the tree to recover, therefore, growers should not let tree Mg levels fall below the optimal range.