|I purchased my home 1.5 yrs ago and inheitrated a mature 10|
|When there's an iron deficiency, the leaves will be yellow but the veins within the leaves will be bright green. This condition is called iron chlorosis and chelated iron will help improve the situation. Iron can be applied to the ground under the tree canopy at a rate of one pound per half inch of trunk diameter measured 4? feet above the ground. It needs to be worked into the soil and then watered in well. It can take several months for the treatment to be effective and you actually see results.
There are other reasons for yellowing leaves in maples; nutrient deficiencies, poor drainage, root diseases, etc. There is also a condition called maple decline in which branches actually die as the disease progresses. It's really difficult to diagnose a plant problem without actually seeing it so you may want to consult with an arborist or other specialist at your local cooperative extension office. Contact Colorado State University Cooperative Extension, 1525 Blue Spruce Drive, Fort Collins, CO 80524-2004 phone (970) 498-6000. Best wishes with your maple tree!