Thank you for all the excellent thoughts all, and sorry to disappear; I didn't realize the thread had grown so! The insufficient sun query is an interesting thought; up until a month ago, we had a MONSTROUS tree in the yard (which is very small) which certainly affected the sun in the garden area. We had it removed after it threw two giant limbs at our house in a one month span. It hasn't really been long enough to see what sort of an impact that will have and the black spot was already well established at that point, but I hadn't thought of that. I do like the idea of replacing a couple of the more damaged plants with modern varieties and seeing how they fare next year. Combined with the added sun, I'm sort of excited to see what sort of a difference it makes. In the last week, most of the plants have shot forth new flowers, which was pretty unexpected- they went from bare to bud to flower seemingly overnight. The humidity has been MUCH lower and the whole garden seems to be breathing a sigh of relief. I may see if I can get some pictures before the flowers fade. Thank you for all the guidance. I'll keep checking in and I'm sure I'll be back with more questions!

Absolutely do NOT keep them inside over the winter. Plant them now and mulch them well. I make a cylinder of chicken wire to go around my more tender roses and new plants, then mound them with a bit of compost and fill the cage with leaves. Works wonderfully! You don't want to mulch like this until the ground starts chilling down considerably however, as in this weather they will cook. In spring just as it's starting to think about thawing remove the cage but leave the leaves. Remove them layer by layer as thawing occurs and the weather warms so you don't shock your rose. -Marie

Prune well beneath the canker and dispose of all the prunings by bagging them and throwing them away. Disinfect the pruners between plants. Cut at about a 45 degree angle and make sure your pruners are nice and sharp before you start so they'll make clean cuts. I hope the canker is not too low on the canes or you'll be cutting back the Knockout roses lower than generally is recommended. I remember when Knockouts were first introduced and were touted as being extremely disease-resistant. I have been surprised how many people have had major black spot and canker issues with them....but that is a reminder to us all that resistance is merely resistance, not immunity.

Chalk it up to a learning experience. Some people say if the ground is not frozen, you can still plant outside. And, if it was dry in the store and dry when you got it home, it was already a goner. They need to be kept watered, and they need a lot of light. You can try to save it, but they are not an indoor plant. Always check on the overall condition of the plant before you leave the store. There is a reason why it was "on sale". Here is the primer on "gift" roses: How to save a potted gift rose Also check out: questions about the winter Consider it a nice temporary decoration. If you want to try again, then next spring (early May), go find one that is fresh and has been watered. Bring it home. Follow the directions in the "How to save" thread, and plant it outside. You'll have a nice plant.