A unique formulation of water-soluble iron effective in trees suffering iron deficiency where application of iron to the soil or foliage is ineffective. Such iron deficiencies are normally associated with calcareous, arid, or sandy soil conditions. Trees most susceptible include a range of eucalypt species, pin and white oak, black locust, birch, liquid amber, pines, magnolia, bauhinia, dogwood, podocarpus, poplar, citrus, peach, pear, apple and avocado.