What I would do is cut off what you can and sanitize your clippers between cuts with Listerine. Until the cuts heal, don't get the cuts wet--keep them dry. It's something you are more likely to see in cool or cold damp or wet conditions.

I try not to prune in damp/rainy weather any more, because I see canker sometimes develop on pruning cuts then. I don't see it develop when I prune in sunny, dry weather.

Don't worry, your roses will be just fine. It is growers in areas with bitter cold winters or those who are in the Black Spot regions that have the real challenges.

Thank you very much for the advice! You've eased my mind a lot. I was afraid I'd lose my roses.

Because of what you wrote, I now think I know what happened. After she pruned the bare roots' stems, the person plunked them back in the soaking water to wait while we prepped the soil. So, the cut ends got soaked before planting, setting the stage for canker to grow. I live on the ocean so it's often overcast still, probably helping the canker to spread. I'm heading out to the garden now to trim them as you suggested. Should I put something on the fresh cuts to seal them?

Again, many, many thanks!

Hi! I am not a very green thumb but I just found canker on my Don Juan Rose also and realized it was because I did not cut the stems properly at an angle and also did not sanitize my clippers.
I read that if it is definitely canker you should BURN the old stems so it does not spread to other plants and I also found a product at the nursery called "Pruning Sealer" to keep anything out of the freshly cut stems. Some people use it, some don't but I am a beginner so I can't take any chances. I had to cut my climber all the way down and don't know if it will live, but I am praying!

Thanks for the advice on "Pruning Sealer". I'll ask around for it at our local nurseries. I trimmed the bad stems off my roses with sanitized clippers and am crossing my fingers the problem is solved.

That rose lady must have been thinking all her roses get this problem and so just cut out the dead canes and the rose will grow more canes. But, when all the canes are gone, you have a problem. You should not have allowed her to prune them. You should prep the soil before you plant, not while you are waiting. Pruning seal means no new grow can come there. If the rose is already infected pruning seal won't stop the infection. Once the fungus has colonized in the wood, there is no way to get that fungus out of the wood, as far as I know. If I am wrong, someone tell me out to get that fungus out of the wooden cane.