My knockout roses are dying
My knockout roses are dying one branch at a time. Many of the leaves have holes and grey-white spots. The branches on several of the bushes have withered and died. There is some new growth and buds on some of the bushes.
It sounds like you have insect and fungus problems with your rosebushes. The new growth shows that they are fighting whatever it is to try and survive. I would suggest spraying all of the rosebushes with an insecticide and then spray them with a good fungicide about 5 days later. Make sure to water the rosebushes well prior to both applications. Please check out these articles links:
Be sure the rosebushes are well watered and well fed. Also keep an eye on them as I have seen something similar to what you describe happen to the canes when a dog as relieved himself upon the roses.