Good afternoon!

We have 2 Autumn Blaze Maples. They were planted about 5 years ago when we built out house, along with all the other trees.

Last fall one of our Maples lost every leaf a month before the other even started. It's leaves have never been very large, always small.

When they fell off last year, we noticed they were black. Didn't think much of it until this year, when they turned black almost immediately (80% of the tree already).

While trying to research this issue, we kept coming up with answers such as "its blisering", or "fungus" or even "it's just low in iron".

The other matching tree is only 40 feet away, and it seems very healthy.

The sick tree has never turned red - only yellow in the fall. The healthy tree turns a burning red.

Both get watered using the same system. (Up until recently, where I've been trying some additional water)

One article I read hinted at a fungus because it was too wet, yet we live at a higher altitude in the "Utah Desert" in a zone 5. If anything, it's too dry up here as evidenced by my brownish lawn. :)

The neighbors maples are growing like wildfire, where ours seem to be growing rather slowly.

All the trees have fertilizer spike treatment every spring, so I don't see how it could be an iron issue, but maybe it is.

PH balance issue in the soil maybe?

Looking at the picture, can anyone give me a hint to what I need to do to save this tree? I'll reply back with any questions or information you need.

Thank you!