I have an 11 year old sugar maple. For the past few years the leaves have been getting more and more yellow. I bought an iron product, read the directions, and sprinkled it around the base. Instead of turning green the leaves are still yellow and small brown spots all over them. Help!



It appears that the tree is suffering from iron chlorosis.  Enough iron is present in the soil, but it is in a form the maple is unable to uptake.  Conditions that make iron chlorosis worse include excessive irrigation and cool, moist weather.  There are no simple solutions to treat the problem.  It is best to plant species that are more adapted to our soil.  However, a soil application of chelated iron containing EDDHA as soon as the snow melts off or at least before the tree leafs out in the spring is a good option.  Other forms of iron (EDTA or iron sulfate) generally are bound up in the soil too quickly to be effective.  This type of treatmetn is good for one year only.

If this does not correct the problem, trunk injections are another option.  They can last 2-3 years but injure the tree somewhat. 

Keep in mind that treating iron chlorosis can be tricky and success is not guaranteed

Posted on 10 Jul 2009

Taun Beddes
Horticulture Agent, Cache County

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