I don't live in a cold climate so I won't address winter protection, but it may be that you will need to consider getting roses that are more cold tolerant. A few favorite roses that you fuss over is one thing, but a garden full of them would be a tedious chore, at least in my opinion. GW member Riku produces an amazing and beautiful garden every year despite living in a cold zone of Canada, but he works much harder than I am willing to do. Look up some of his old posts to see how he does it.

The European once blooming Old garden roses (OB-OGRs) include some very hardy roses, the gallica class in particular. Some hybrid perpetuals are fairly cold tolerant, and many of them (not all) repeat. The rugosa roses are very tough. Some don't like their informal style, but in my opinion, their incredible heavenly fragrance of roses and cloves puts them at the top of the list. You might look at roses developed in the Canadian Explorer series for hardiness. There have been rose breeders who used hardiness as a criterion, Griffin Buck being one that comes to mind. There is a revived interest in his roses, and a number of sources now carry them.

Finally for those few tender favorites you simply must have, try getting them on their own roots rather than grafted. No, this will not make them any hardier. But if they do die back to the ground, at least any new growth in the spring will be the variety you chose and planted rather than root stock.

Good luck to you. Everyone faces challenges in their garden. It seems yours is very cold winters. Fortunately, there are lots of choices that will still allow you to have a lovely garden full of roses.

Rosefolly

Actually, I just now looked at your zone, 7B. I think I overstated what you need to do, since that's actually not so very cold. Right now you're thinking to yourself, just what does she know about zone 7B, she gardens in zone 9. Very true, but I grew up in zone 6A/5B of western Pennsylvania. That was tough on roses, but even there, roses could be grown with moderate care. In fact my great-grandmother in interior northern Maine (5A/4B) grew a rose or two back in the 1880's. I still have a plant gown from a cutting taken from her original dooryard rose.

If you keep away from the very tenderest of roses (teas, chinas, noisettes), you should have no problem with varieties. In fact you can probably grow the OB-OGRs much better than I can, lucky you. They like a bit of winter chill.

I'm wondering if your problem might actually be that your roses are in a windy area? That can really increase the problem of cold. Or perhaps your dieback problems could be caused by alternating freeze and thaw. If these conditions are present, they could stress your roses. If so, you might consider either a windbreak (to filter the wind) or a mulch after the first hard freeze (to stop the freeze and thaw cycle). I admit that I am getting out of my experience zone here, so I will leave it to others who garden in colder climates than mine.

Rosefolly

I wonder where the OP lives and what low temperatures she has experienced there. Although there are a few super-tender varieties, I'd say 98% of roses, including old teas and chinas, should survive a winter low of +5 F in the climate of the eastern US. That's the usual seasonal low around here, but in the past 5 years I've lost only one plant to winter--and that was a fluke probably not caused directly by temperature.

However, in answer to the query, it is certainly feasible to raise the bed around the extant roses. Roses adapt quickly to a change of grade. It might help them grow better if the soil is shallow and stony. The soil should be similar to what's already there.

It was an unusually cold winter and a big part of the country rec'd temps below their zones. I had a lot of dieback, not so much actual death. It is very disheartening for nice sized roses to get knocked down to the ground.

Take heart, this unusual winter is not the norm. But it is a possibility that just happen to come true.

I live in an area of extreme and extended dry summer heat plus cold, dry winters. And for most of my roses (including cold hardy OGRs), it is the cold, not the heat that does the most damage.

I don't do the winter protection, too much work. They will have to either sink or swim.

I have a problem with the really tender roses, but this past year I lost a grafted climber that should be totally hardy. It looked great going into winter.

We actually didn't get very cold this year, as far as minimums go. I'm really wondering if I have a winter dryness problem? You may, too?

The rose acted like it was from cold damage, but I have a suspicion it just had some fake green in it from the cold preserving it, so to speak. It gave up the ghost as soon as it should have been starting to bud.

I don't know. I don't even think it was the wind, though. We weren't very cold.