Blueberry leaves turning red in the summer
I planted 7 Blueberry plants last fall here in the Memphis TN area --4 O'Neal's and 3 Misty's, both of which are southern highbush. I got them from Stark Bros. in the small containers.
I used 100% sphagnum peat moss as the soil and put a couple of inches of pine bark mulch on top. I have done 2 applications of fertilizer using "Berry Spikes" (Link: http://amzn.com/B00A4EDVTY) once in the fall and once in the spring.
I didn't water much at all in the fall and winter and water 2-3 times a week now that it is summer depending on the rain we get. I try to do it every other day.
As far as growth goes, they maybe have grown 2-4 inches this year so far. (Not sure if this on par or not, since one of the O'Neals has grown 8 inches)
Nevertheless, I noticed that some of the leaves are starting to turn red on 4 out of the 7 plants. Overall, the plants don't look very healthy to me.
Here are some pictures: