What on earth ?
My 4 year old Triple Crown blackberry has morphed into these odd ribbon like canes. Others are amazed and we are enjoying watching progress but, could this be a bad thing?
Certified GKH Gardening Expert
By the description, I am unable to identify what is going on. Can you include a picture? This will help me to help you. In the meantime, here is an article on blackberry care: https://www.gardeningknowhow.com/edible/fruits/blackberries/growing-blackberry-bushes.htm