As for acidification i once applied peleted silfur, 3 to four years down the row and the pellets look still as new, havend degraded one bit , they are burried, the ones on the surface are the same. Ive thought to hammer the pellets , until they get a flour consistancy, and apply that.
I must say that all of my blueberries do not usually show any sighns that the soil may be too alkaline. The container ones are planted in a clayey soil, with forest soil added to it, along perlite, not ideal if you ask me, but they are doing very good, ladt year they had a heavy crop, this year will be a lighter one.
I have one bush also planted in a clayey soil, inground, also doing wonderfull, dark green leaves at all times trough summer.
I havent used any acidification on all of them, also do not fertilize that often, which is an irony in relation to the topics name😂, i just cannot get to fertilize regularly.....