Sunday, July 12, 2009

The Golden Maple

Dum dum DUUUUUM. Today I'll be talking about the beautiful yellow maple. You know the one. It's across your street in the neighbors yard, shining brightly. It might even be in YOUR yard and you're scratching your head trying to remember if you had bought a yellow maple. You could have SWORN it was green last year!! Let's take a closer look at this beautiful tree....

Wait. There's something odd about these leaves. They have GREEN veins, but the rest of the leaf is yellow...

What you're seeing is not a yellow maple, but a maple suffering from iron chlorosis. Chlorosis means lack of chlorophyll. Iron chlorosis is a condition caused by lack of iron. No one is absolutely sure what causes iron deficiency in the soils. Chlorosis is typically associated with one of three site conditions--a soil with a pH above 7 (an alkaline soil), a heavy soil containing a high percentage of clay, or a site where there has been extensive soil fill or removal, compaction, or construction injury that has damaged the root system. We live in Colorado, and most of us have the two site conditions in our backyard. With all of the rain, a lot of the iron has been washed away, and chlorosis is happening all around town. Some maples are more susceptible. Amur maples, silver maples and Autumn Blaze maples seem to be the top three. Oak trees also can suffer...especially the Pin Oak. I'm seeing chlorosis happening in Aspens, Ash trees and even my own Mock Orange is suffering a bit.

What to do? There are a lot of products that have pure iron in them. Dr. Iron is a granular type that you can put around your tree's drip line and water it in. Quite a few web sites say to punch holes in the ground and then put the iron in the holes. You can also use foliar spray that has iron for smaller trees and bushes, but good luck spraying the entire tree. It might take a few doses to bring your tree around.

Although those "yellow maples" are pretty to look at, don't hope for one. Chlorosis is a killer to your plants. Treat them as soon as you see it happen.

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