Hi Zach, 

just a few questions before I develop a more detailed answer for you. 

Iron deficiency can produce the situation you are seeing in the maple leaves so no argument there.  But this condition can also be produced by a lack of manganese and/or magnesium in the plant.  Have you checked these possibilities out?

Also to provide you with my best answer, I would like to know the pH of the soil surrounding your maple.  If the pH is too high (greater than 7.3), the maple won't be able to take up iron/magnesium, manganese.  If this is true for the soil around your maple, administering EDHHA iron will not accomplish anything and will be a waste of your money.

Have you recently had an analysis done of the soil around your maple?

I am looking forward to your response so that we can quickly get to some resolution.

Thanks for using our forum.

Thanks for the response.  Good progress.  Please research the magnesium/manganese aspect.  You will be in the best position to determine whether or not it might be applicable for your situation.  I will value your opinions.

With respect to soil testing kits, please be advised that these DIY kits are notoriously unreliable and inaccurate.  Nevertheless, I will be interested to hear about what results you obtain.

Thanks for consulting with our forum.

Just doing a follow-up.  Have you done your soil analysis and have you received a report?  If the latter, I would like to receive a copy of it to finalize an answer to your original question.

Many thanks.

Will look forward to seeing the soil analysis results.  Thanks again for using our services.

Thanks for the soil report.

It does appear that there is an iron deficiency in your soil. The levels of magnesium and manganese are sufficiently high to eliminate these two nutrients as causes of the chlorosis. Perhaps most importantly, the pH is on the acidic side. Had it been on the alkaline side, that would have presented you the challenge of lowering the soil pH before dealing with the chlorosis issue.

There are two principal ways to correct this iron deficiency:

1). Applying an iron chelate to the soil around the tree. This is a form of iron that is more readily absorbed by the tree, even in alkaline soils. The EDDHA product (Sprint 138) that you are considering is an iron chelate. The opportune time to apply this to the soil is in the spring. The next best time would be now (late summer, early fall). In looking at the product label for this specific product, there is the statement “For Professional Use Only”. This raises the possibility that you may have trouble obtaining it. It contains 6% iron by weight. See:

https://www.domyown.com/sprint-138-chelated-iron-p-10255.html?utm_source=google&utm_medium=cpc&utm_campaign=PMax%3A %28ROI%29 Shopping - Professional Turf %26 Ornamental - Smart&utm_id=<personal data hidden>&utm_content=&utm_term=&gad_source=1&gclid=CjwKCAjw_Na1BhAlEiwAM-dm7EFkkCgvBg7dRwI6FdqgFB54g0wzlTV6tl63yVMFPQIIAlcCDx_CCRoC74UQAvD_BwE - gallery-1

If you goggle iron chelate for soils, you can fine products containing 10% iron by weight. These might be easier to find. These products might also be available at gardening centers.

Whatever the source of the chelated iron, apply the product according to the directions on the product level. See the following for suggested application dosages:

https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1415.pdf

2). In severe cases, use an iron chelate foliar spray. This provides a more immediate, though temporary, solution by allowing the tree to absorb iron directly through its leaves. You may want to consider this as an initial step before using the powdered form of iron chelate. These sprays should be available at most gardening centers. Once again, abide by the application instructions on the product label. However, given the size of your tree this may not be a feasible approach. See the following:

https://blog.bluelab.com/iron-deficiency

https://extension.usu.edu/forestry/trees-cities-towns/tree-care/preventing-iron-chlorosis

https://www.extension.purdue.edu/extmedia/BP/BP-27-W.pdf

Good luck. Certainly get back to us with any further questions.