I have 2 blueberry bushes that I bought almost a week ago, I say them both outside in 4 gallon containers (occasionally bringing them into our unheated patio if it got super cold since they have spent so much time indoors at the store) when I got them the leaves they had formed were all green. Tonight when I went out to bring them in after a few nights outside in 30 degree weather I noticed the leaves were a brownish red color but they don't look shriveled or anything otherwise. Some new buds have even opened but they are the same color.

It's been raining so I know they have been getting plenty of water and I have it in pots where extra water can just flow out so they aren't waterlogged I don't think. I also made sure to plant them in acidic soil. Is it normal for blueberry bushes to get this color this time of year or should I be doing something different?

Thanks for your help :)