I would just remove all deadwood only. Water the rose well. Do not fertilize as it often harms weak an recovering plants.
If the sun is scorching (lucky you! here it is still relatively cold!) then protect the rose by placing something nearby to give it some shadow (e.g. a box, an umbrella, etc).

What could you do? I'd just wait and see. Don't be too much worried. A bad start can happen, but roses are hard to really die .

I have the same problem with several of my roses, and I appreciate the advice, scardan123. I'm afraid I've been doing it wrong, I've been feeding them like crazy. But as nickelsmumz8 said, I am afraid to cut down any of the canes when the only leaves they have are at the very top.

All the feeding, watering and everything else wont help a rose that is obviously very susceptible to D. rosae (BS) and is severely defoliated. You can either try to save the rose by getting rid of the infection or watch it die.

From your header we can't tell whether you live in Seattle or South Georgia. Please fix that.

Jeez, Michael, it's not like a list rule or anything. No need to snap. For your information and as I mention in many posts, I'm in Portland, OR.

Henry, this is a mature rose bush. I don't know how old it is but I would guess ten or more years. I'm assuming it has a pretty decent root system. I will probably cut it back very hard in the winter, but I don't want to do that now while it still has some leaves to feed itself with. If it were three years old and doing this badly I would probably let it go, but this rose was pretty lovely when I moved here. I'm not experienced enough to tell whether this is a temporary downturn or the beginning (middle?) of the end.

Nickels, sorry, didn't mean to sound snappy--I did say "please" :)

You'll notice all the regulars here include their state in the header-- there's a good reason. For example, if somebody has a question about what to do about blackspot, the answer depends on whether it rains there in the summer.

Roses need their leaves to produce energy and prosper, so if it's losing leaves due to BS, it is going into winter in a weakened state and will continue to struggle. Since you don't spray for BS, this is a rose that will continue to decline.

I do spray fungicide because I live in a high BS pressure zone, and even some of my HTs still struggle with BS at times. It's a nasty thing, BS.

Nickels, nothing will reverse this except treatment with something like tebuconazole. It doesn't matter how strong the rose is. I have well established mature roses that would perish in a couple of years if they were not sprayed for BS. Most modern roses would be defoliated here by mid summer and sooner or later they would be killed by the winter. D. rosae is a disease in roses like cancer is in humans that left untreated in the northeast is usually fatal. I understand that it is not a big problem in some dryer parts of the country or in certain years and there are roses that are more resistant but if you have a rapidly defoliating rose it seems to me that you have to spray or risk losing the rose.

I'm going against all the advice from others. Were it my bush, I'd remove 1/3 of the old canes down to within 12 inches of the ground. New canes with foliage should grow from the remaining stubs. You'll get more help from the many new leaves than from the tiny ones way up on the bush.
Don't cut back in the fall. Wait until spring or your normal pruning time. Nutrients stored in the canes help the bush overwinter. Cutting off these food stores in fall removes what the plant needs to help it survive the winter dormancy.
Next year when you prune, remove another third of the old canes followed by the last third the next year. You'll end up with a stronger bush with younger more productive growth. Keep the area around the bush clear of anything that might prevent good air circulation. Excessive blackspot suggests that moisture sets on the leaves too long allowing the blackspot spores to germinate. Better circulation will let the leaves dry and lessen any blackspot pressure. You'll still get blackspot unless you spray a preventive fungicide but not so much.
All my bushes are exposed to lots of air circulation. I don't spray but still have less blackspot than many who do. As I deadhead, I attempt to keep the centers of the bushes clear of excessive and blind growth so air can flow freely.
Old canes can become non productive and bare on the bottoms. Aside from periodically removing them there's nothing you can do other than remove them to force long dormant buds to produce new canes.
Each spring and during the summer if I notice a cane on any bush that's getting old or non productive, I cut it back.
This year a number of my bigger older rugosas experienced this ruthless pruning. They've all responded with fuller bushes and more blooms.

There are two trains of thought here. One is how to cure BS and prevent it from ever occurring again and the other is how to best live with it if you don't spray or spray very little. I have never considered the latter option. It seems to me to be vastly less work and more satisfying to get rid of BS once and for all than to avoid spraying and have to constantly fight a losing battle against ugliness and defoliation. Unfortunately, there are a lot of people that think you can keep BS at bay without spraying in places like the northeast which is simply not true. Keeping them alive and keeping them in top condition are not the same thing.

Henry, I'm not going to spray, so if the rose can't hack it without spray, it's gone. I'll live. It's a lovely rose, but I'm sure I can find a nice fragrant red thing that will be happier here. The blackspot pressure isn't that bad here. I'm not even sure there's that much blackspot on this rose... it's defoliating, but maybe there is also something else going on.

Karl, I like your idea. It sounds like my kind of plan (if only I can remember what I was doing six months later). This plant is now wide open and has plenty of air circulation -- I think it was fine anyway. It does have bare lower canes and I was thinking one reason to cut back was to force some new growth lower. The rotating plan makes sense so as not to lose those leaves currently producing some food for this beleaguered plant.

I normally prune in about January -- I understand mid-February is more appropriate here. It gets me because the neighbors across the street, who have lawn guys and gardeners in every 20 minutes, prune earlier, and the little row of shrub roses always blooms like mad all summer. I'm sure they hate me anyway... I'll just wait this winter.

Should I take out all the flowers to try to save energy?

Off to my loppers.

Enjoy the flowers.

Yay! I get to lop AND I get to enjoy the flowers!