I have a highbush blueberry bush that's leaves have turned prematurely reddish purple. They veins are still green for the most part. This started back in June, so its not weather related. It primarily started on the older growth the woody branches and stems. Now the green stems from this past year are starting to turn colors into this reddish-purple color. The bush produced a good crop of fruit this year. Its a 4 yr old bush. Some of this tips of the branches have droped a few leaves and are dying. I was hoping this is just older growth that needs pruned out net spring.