What is causing this?

[JB_]

We have a variety of red maple that is having some problems. I'm in the Utah Valley, ZIP code 84003. It's affecting the leaves on the ends of some of the branches, but not all. I know our soil has a high Ph, but I'm not sure what it is. Some branches have greener leaves and some have yellower leaves. I've been told iron chlorosis, but wanted another opinion before I start treatment. Do you need more information to know if that's that the right diagnosis? I have no experience with this myself. I'd appreciate your insights.

Thanks,
John

 

[Bucknut]

I’m not from Utah, but that sure looks like chlorosis to me. The leaves should be a much deeper darker green ideally. Not sure how others treat, but we macro-infuse with Ver-Dur from Rainbow Tree Care. Good for up to three years “green up”.

I would note we have had mixed results with red maple. Sometimes very difficult to excavate the flare due to the amount of smaller roots in the way, which can lead to poor/slow uptake.

Also, we typically treat in the fall, since a heavy dose of iron will cause fairly rapid defoliation. We find this is not ideal since:

1. Customers freak out if not aware of this
2. No need to stress the tree in the summer by
asking it to re-leaf unnecessarily.

Optional would be to add a growth regulator (e.g. Cambistat) since you’ve already dug a trench at the root flare. Theory is that it significantly slows new canopy/leaf growth while encouraging new root growth, which should help the tree to extract more iron from the soil in the first place.

 

[Wyoarborist]

With maples it's not always just an iron deficiency. Often manganese deficiency is part of the problem. I like the PGR idea. Maples are sensitive to PGR and can easily be over regulated tho