My guess is its just some winter damage, and I wouldn't worry about it unless it persists a month from now. But do check some of the canes you pruned back. Is the center white? If not--if its brown--then you have cold damaged canes that need to be cut back until you come to white interiors. Try cutting back several inches at a time, until you get to the white. I'm not sure about Knock Outs, but on hybrid teas, they sometimes need to be cut back to 6 inches or so from the ground. I wouldn't think KOs would have that much problem, however. Good luck. Kate

What are you spraying with? What you need is a systemic fungicide. I strongly recommend Bayer Advanced Garden Disease Control for Flowers and Roses. (Don't confuse it with the other Bayer products--I do not recommend them.) The Bayer Garden Disease Control can be found a Lowes or ordered online. If you have a new outbreak of BS, spray this product weekly for a couple weeks. Then back off and spray only every 2-3 weeks. If your weather gets very hot in mid-summer, you may not need to spray then since very hot weather is not conducive to BS. On the other hand, if your new growth is healthy, don't worry about it. As to the yellowed canes, I have no idea about that, but overwatering can cause a host of problems. Hopefully someone else can address this problem. Kate

Thank you for all your support and good wishes when I was feeling desperate and panicky. And I am sorry i did not get back sooner. Some of what I have been able to figure out is good news. a) My roses do have severe, I mean all leaves gone, black spot. This rose nook looks so sad. I could not find the Bayer product suggested but I found an Ortho product with chlorothalonil in it and is supposed to take off black spot and I have started to use it. The literature on the bottle says it is supposed to take care of spores too. Over 5-6 days I did not see much improvement. The black spot keeps spreading. One other thread on this forum suggested Mancozeb as the best product to use. I just order it today. Lets hope for the best. I am taking care of the mulch. b)The other damage, as suggested by rosefolly and oldroser IS chemical damage from sprays and new growth looks good. Because of what looked like black spot to me I had asked my husband to spray a complete fruit tree spray also recommended for roses. But he must have used the wrong concentration. Anyway not too much damage done. But I am wondering what is going to happen to the roses that have lost all their leaves? Essentially no growth and strength from this summer? Or actually a set back? Should I cut back the canes that lost all the leaves? Will this stimulate robust canes to grow in? Any other information regarding black spot is all too welcome. Thank you so, so much for your suggestions and support. Katyajini

It looks like winter damage to me. Prune a cane to see if your pith is clean or brown in the center.