Cache Valley experienced a wetter than normal spring (again!), and all that extra water leached many of the available micronutrients from our soils - Iron especially. All it takes is a few weeks of hot, summer weather, and suddenly we see sample after sample of iron deficient maples, raspberries, spirea, oak, roses, and many other common plants. The telltale sign of Iron Chlorosis is a lighter green or even yellowing of the leaves with dark green veins running through the pale-colored tissue.
Iron deficiency shows up in the newest growth or the most recently produced leaves first, then gradually will develop in the older leaves as well. The high pH of our soils (usually between 7 and 8 on the pH scale) compounds the problem, making many forms of iron and iron supplements unavailable to the plants as it binds up the iron and won’t allow the plants to absorb it. The most effective form of Iron you can use to supplement your plants is a pre-digested form (or chelated) Iron that works in soil pH that is above 7 or higher.
We recommend either the liquid Iron Combo Chelate from Monterey-Baicor (made right here in Cache Valley) or a powdered version called EDDHA Iron Chelate. Both of these forms of iron will be instantly available to the plants and can correct a deficiency in just a few weeks depending on the size of the affected plant. Both can be mixed in water and applied as a foliar spray or applied to the soil as a drench. If you are experiencing this problem year after year, using soil sulfur to lower the pH of the soil helps considerably, as well as a preventative application of the chelated iron early in the year before the symptoms start to show. For larger trees (6in. Diameter or larger) The Iron Tree Treats by Monterey-Baicor make quick work by introducing the Iron (among many other nutrients) directly into the sap flow of the tree.