What is wrong with my maple trees?

Asked July 8, 2015, 5:15 PM EDT

I have some maple trees in the yard. We have very clayey soil. Late last summer the leaves looked like they had mold or fungus. I took a picture to a greenhouse and they told me to use Fung-onil or just wait until it freezes. I used Fung-onil, and then again this spring when the leaves looked like that. The trees are 10 to 12' but are not growing much and do not look healthy.

McCook County South Dakota maple trees chlorosis

3 Responses

The problem is not a fungus but chlorosis due to the lack of either iron or manganese. The problem is not that the elements are lacking in the soil but the high pH makes the elements unavailable to the trees. You might try spreading a chelated iron fertilizer and this may help improve the color.


Thank you for the response. I did put some chelated iron on the trees (mixed and poured on ground as well as mixed and sprayed on leaves). How long should it take to green up if this was the issue? If this doesn’t pep them up should I take a soil sample somewhere to be tested? Where would I do that in the Sioux Falls area?


Dean Kueter

Montrose, SD

The response may not be till next year and you should apply again next spring. The pH is the issue, not the amount of iron in the soil. You might check with your local garden centers for a pH test. If its above 7.5 even fertilizing may not work.