Do you know your soil pH prior to adding the Ammonium Sulfate? You can't get accurate results now as sample contamination by even a small bit of undissolved Ammonium Sulfate will through off the pH number.

I do not, no. Is it possible too much acidity could cause this?

It looks like salt burns from either too much fertilizer or fertilizing when soil was too dry. I would always mix Ammonium Sulfate with water first, and you might ever water the night before with water. I have burnt leaves by adding too much fert and watering when plants were dry. I used to use 1 tableshoon per 2 gallons of water but now only use 1 teaspoon for every 2 gallons about once a week.

I flooded during Harvey and all my BB in small pots died. However, all the 20 to 25 gallon bushes seem healthier this year as far as leaf color. I think I had salt buildup from over fertilizing that was cured by the flood waters flushing out all the salt. Not suggesting doing this but I am not going to push the BB with too much fertilizer.

Gary, I am surprised you are not growing your Blue Berries in ground given your location.

Ike

The place I had in Beaumont was a tight clay, good for rice farming but not much else. Where I am at now it would be easier to grow in the ground. Some I will transfer to the ground but some I may leave in pots since they are already there and doing well. I have them close to the house where I can keep the deer and to some extent the squirrels away. Blueberries need good surface and internal drainage. I had the surface drainage but not the internal.