The same thing happened to me last year when I planted a blue berry in the spring. I think the first thing I would do is check the PH. I don't remember all of the causes but I found that there are a number different things that can cause that, some are more serious than others. If you don't have one already you can get a soil ph probe for pretty cheap. I don't know that they are super accurate but at least it would give you an idea about whether the ph is in the right ball park or not.

In the end I didn't do much with my blue berry last year, just kept it watered, and added more soil acidifier this spring. It looks great this year. It'll be interesting to see if anyone else has more insight about this.