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Brown spots on leaves #879539

Asked July 31, 2024, 9:44 AM EDT

I have a customer here looking to determine what is wrong with his tree. The leaves started to turn a yellowish color and started getting brown spots all over them. Can you determine what's wrong with it and how to fix it based on these photos? Thank you!

St. Clair County Michigan

Expert Response

I believe you have two issues impacting this tree. The tree looks like a commonly sold hybrid between red maple and silver maple called Freeman maple (Acer x freemanii).

The yellowing appears to be iron chlorosis, which is likely due to high soil pH (which essentially limit iron available to the plant). Red maples are particularly sensitive to this issue. If high pH is indeed the issue, there isn't much that can be done for the tree other than planting a tree in that location that can better tolerate higher pH soils. You can't lower the pH enough around the tree to make any lasting difference. However, technically there are applications you can make to increase the iron in the soil in a certain area, but they are expensive and have to be applied annually.

Before considering any soil application or alternative plantings, I would advise testing the soil in this area to determine soil pH, along with other soil factors.

Here is a link to MSU soil test site:

Home | MSU Soil Test


As for the spots, silver maples are particularly prone to various leaf spot diseases. This appears to Maple leaf blister, which infects the leaves in spring often during wet spring seasons like we have had this year. Here are a couple links to more info on the disease:

Maple Leaf Blister | Yard and Garden (iastate.edu)

Maple leaf blister and anthracnose: Two diseases of maple leaves - Landscaping (msu.edu)

For confirmation on exactly which leaf spot, you can send a sample to MSU's plant diagnostic lab, linked below.

Plant & Pest Diagnostics (msu.edu)

An Ask Extension Expert Replied August 04, 2024, 10:48 PM EDT

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