Hi Troy, 
Thanks for the question. I can't tell from the image what might be going on, but I am wondering what the roots look like - we might find important clues there. 

The scorching could be due to damaged roots that may be struggling to take up moisture. It could be due to properties of the soil or amendments that were added (like fertilizer burn). Phytopthora root rot is possible, especially if the soil is overly wet (we'd need to see the roots to get a better idea). And, I don't think it is due to the heat. 

I would like to invite another specialist to chime in. I'll see if I can assign this question to someone who has more experience with blueberry problems than I do.

Hope this helps!

-Kasia

I would recommend visiting with Jennifer Jensen at <personal data hidden> or<personal data hidden>. I am in southern Idaho where we don't even think about growing blueberries due to the alkalinity of our soils. Jennifer is up in Northern Idaho where they grow wild.

Thanks,

Hi Troy,
The specialist I reached out to suggested that you contact Jennifer Jensen at <personal data hidden> or<personal data hidden>. Jennifer is up in northern Idaho where they grow wild. Blueberries will not do well in alkaline soils, like what we have in southern Idaho. 

I hope this helps!
-Kasia

Thank you, for your support on this.  I will be reaching out to Jennifer.  

Troy

Hi Troy,

From my diagnosis I would chime in and say it appears to be heat damage (as it's starting from the margin of the leaf and moving inward), especially those 100+°F days.  Though our very high pH here is southern Idaho can cause problems too (as blueberries thrive in soil pH's below 6).  

Thanks,
Brad