|what is the cause of oleander leaves turning yellow and what can be done to correct this problem?
I am sorry for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
That could be due to dry soil or soggy wet conditions or a lack of nitrogen or a disease called Xylella or Oleander Leaf Scorch. This disease has no cure and your best method of dealing with it is to prune out all brown shoot even if it means cutting the plant back to the ground and then maintaining adequate soil moisture.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!