Blueberry leafs tinged with red

This began in August and I don't know what the problem could be. I've posted a pic of the leaves; please let me know if this a disease or nutritional deficiency and how it can be dealt with.

Hope its nothing serious...

Just another note I've never tested my soils pH, I've just assumed living in this area we naturally have acidic soil.

 

This seems to be natural. Mine do it every year, and still bear like crazy. I'm thinking it's a sun thing. Some of mine are already turning colour for the fall.
keke

 

But this is how my leaves were in mid August? Does the same happen to your plants at that time?

 

Mine do the same thing. I fertilize, but don't spray any-thing. I'm in Pitt Meadows.

 

Same here, agree with Keke's suggestion that it is a consequence of direct sun in the hottest part of the summer. Nothing to worry about, they'll get redder yet before leaf drop.

 

Same here, and were in Magalia. I feed and they feed us
Anita Vairo