What is it? It is a deficiency of chlorophyll, causing yellow discoloration of leaves that should be green. Ornamental trees sensitive to iron deficiencies include American Elm, Cottonwood, Jack Pine, London Plane, Magnolia, Maples, Mountain Ash, Oaks, Walnut, White Pine and Yellow Birch. Iron deficiency in conifers is indicated when the needles turn yellow. In deciduous trees, the leaves yellow while the veins remain green. ArborSystems Nutriboosters relieves symptoms of iron chlorosis and boosts tree health…trees change from sickly to healthy darker-green in days. For more information on the various Nutriboosters formulations that work for different tree conditions, click here.