Sick Red Sunset Maple trees
Dear Sir or Madam, My Red Sunset Maple Trees are sick, the leaves turn yellow with dark green veins every August, although in springtime they are doing good. I tried magnesium, manganese, nitrogen, potassium,..then I read it is probably iron deficient. I just don't know, does the test kit test for iron and manganese?.
Yes red maples struggle in clay soils where the pH is very alkaline. Adding additional micronutrients to a soil with a high pH will not green up the plant unless it is in a chelated form. Chelated nutrients resist being bound to soil and allow the plant to take it up. A high pH soil causes available iron and manganese to become bound to the soil. Acidic soils do not bind up the nutrients to a degree that causes deficient plants. With fruit trees commercial growers will have an analytical lab run tests on leaf tissue for Iron and Manganese deficiencies. Often the tissue test is accompanied by a soil test to determine if these nutrients are found in the soil but are bound up. Determining whether it is from iron or manganese is very important. Usually with red maple is more likely to be manganese but this can be determined by spraying leaves with a liquid chelated manganese or chelated iron. this is usually done in late spring to early summer. May not be practical for big tree. You can contact the MSU Soils Lab to discuss submitting leaves for a tissue analysis. They can be reached at: Phone: (517) 355-0218. Also more information on chlorosis of plants and how to treat it is found at the University of Minnesota Extension at: https://www.extension.umn.edu/garden/yard-garden/trees-shrubs/iron-chlorosis/