Hydrangea illness identification

Please let me apologize for posting this in the wrong section (if I have). I wasn't able to find the correct thread.

My mom loves her plants and takes great care of them. But her hydrangeas are starting to develop these spots (but only a few of the leaves have them). Can anyone help me identify what is causing the spots and is there anyway to treat it? I've attached pics. Thank you for your time!

 

Could you give us more information, please? Are the hydrangeas well-settled where they are, or were they new last year? Where are they planted (what kind of sun exposure, soil, etc.)? How are they watered, and how often? Are any other nearby plants showing the same damage?

 

Cercospora damage perhaps?