No.

I'm in Zone 6 and provide no winter protection for my roses, although oak leaves from my neighbors' trees often blow through my backyard and probably supply some minimal but very random protection.

Kate

Yes and no. It truly depends on the micro-climates and the roses in your garden. I live in the mountains of northern California at the 2000' elevation level. Generally, I don't bother with winter protection, but I do try to make sure that all of the roses go into winter healthy.

The exception ... I have one very cold micro-climate in my garden. In the years I did not provide extra mulch, the roses came back, but not as vigorously as they did in the years when I did mulch that bed.

If I have a young rose planted just this spring, I'll give it more mulch to help it get through its first winter.

I do mulch all of the beds in fall, if possible, but not for winter protection. I use shredded oak leaves and they break down over winter and are feeding the soil in spring and provide a weed barrier. I also mulch in spring, but that's to prepare the beds for my high summer temps.

Smiles,
Lyn

No. Canes that grew out last spring will not be injured until temperatures fall below 10 degrees. Older canes and the grafts can usually take 5 degrees. Tip growth will be injured in the low 20s, but you can't protect against that. At best you would be protecting a few lower inches of canes that grew out this fall and haven't hardened off. Meanwhile the cover might encourage canker disease.

I am in AZ as well 3400 Verde Valley
I have never covered a rose here(32 of them) I do keep wood mulch at the base year round. Winter to protect roots and to protect the roots from summer heat and keep the moisture in. We have gotten as low as 16 during Jan and all seem to do just fine. I do start trimming in late Dec through late Jan as it takes me awhile.

Michael G ...

Since we get a lot of rain and some snow, I do make sure that when I use a heavier mulch around a rose, that I make a collar to keep the mulch away from the crown of the rose.

So far, I have not seen much canker on these roses.

Smiles,
Lyn