Is your maple looking a little yellow? It’s possible that it is experiencing an iron deficiency. Red maple and the freeman type maples (of which autumn blaze maple is the most common) as well as red oak and several other species of trees common to our area are all prone to iron deficiencies in alkaline soils (soils with a high pH) like those common to Colorado’s Front Range.
|Chloroctic Freeman type maple|
|Chlorotic leaves which are beginning to scorch|
The best way to deal with this issue is to avoid planting species which are intolerant of our soils. However, there are several potential treatments. You can have an arborist inject an iron solution into the trunk of the tree every few years to deal with the issue. However each time you do this you are wounding the tree which creates potential avenues for decay and is generally stressful for the tree. You can also apply a chelated iron fertilizer. These products consist of iron bound up in organic molecules which are stable in our soil. Make sure to use products labeled as EDDHA. There are many types and this is type is best for our high pH soils. These are somewhat expensive and need to be applied annually or near annually depending on the severity of the deficiency . Foliar applications of iron are also a possible treatment but they have their own list of drawbacks. They only green the leaves they are sprayed on so improper application can lead to the tree appearing striped. They can also stain driveways, sidewalks, patios and other elements of the landscape. Foliar iron fertilizers will need to be applied annually. Since it is possible that spring time over watering or issues creating stress for the plant such as soil compaction and girdling roots may be aggravating the issue. Make sure you watch your watering and if possible core aerate around the tree.