What to give my Maple tree to keep the leaves from turning yellow - Ask Extension
I have a maple tree with about a 9 inch diameter trunk. Every summer the leaves start turning yellow and the veins in the leave show clearly in the ...
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What to give my Maple tree to keep the leaves from turning yellow #892781
Asked February 18, 2025, 2:00 PM EST
I have a maple tree with about a 9 inch diameter trunk. Every summer the leaves start turning yellow and the veins in the leave show clearly in the leaf. What should I give to this tree to keep it healthy?
Larimer County Colorado
Expert Response
Hello,
This is iron chlorosis, which is a common ailment on many maple species and common in our urban soils - and is usually linked to an iron or manganese deficiency.
It can be caused by high pH (we have iron in our soils, but the high pH results in a chemical form that makes the iron unavailable to plants), overwatering, soil compaction, and/or salts. Note: is it not practical to alter soil pH in Colorado.
Extension does have a very lengthy publication on this with potential treatments: https://cmg.extension.colostate.edu/Gardennotes/223.pdf
Essentially you'll need to treat the tree with a chelated iron (EDDHA or EDMA). You can do this via trunk injections, soil applications, or you can spray iron onto the foliage after the tree fully leafs out (this is generally not the best option because of the tree height and size).
Trunk injections tend to be the most effective, but needs to be done by an arborist, because you will be drilling into the tree and attaching iron via an "IV" line. Soil applications can work, but are laborious because you drill many holes and apply the iron.
In addition to adding iron, be sure to adjust your cultural conditions and adjust watering. You can also consider aerating to reduce potential compaction.
It might be best to speak to a certified arborist for a consultation and recommendations. You can find one at http://www.treesaregood.com or use the City of Fort Collins's list: https://www.fcgov.com/forestry/arborists
This is iron chlorosis, which is a common ailment on many maple species and common in our urban soils - and is usually linked to an iron or manganese deficiency.
It can be caused by high pH (we have iron in our soils, but the high pH results in a chemical form that makes the iron unavailable to plants), overwatering, soil compaction, and/or salts. Note: is it not practical to alter soil pH in Colorado.
Extension does have a very lengthy publication on this with potential treatments: https://cmg.extension.colostate.edu/Gardennotes/223.pdf
Essentially you'll need to treat the tree with a chelated iron (EDDHA or EDMA). You can do this via trunk injections, soil applications, or you can spray iron onto the foliage after the tree fully leafs out (this is generally not the best option because of the tree height and size).
Trunk injections tend to be the most effective, but needs to be done by an arborist, because you will be drilling into the tree and attaching iron via an "IV" line. Soil applications can work, but are laborious because you drill many holes and apply the iron.
In addition to adding iron, be sure to adjust your cultural conditions and adjust watering. You can also consider aerating to reduce potential compaction.
It might be best to speak to a certified arborist for a consultation and recommendations. You can find one at http://www.treesaregood.com or use the City of Fort Collins's list: https://www.fcgov.com/forestry/arborists
