You don't have to wait for them to go dormant to plant them deep. Just do it now. It will not hurt them at all. I do it with all my new roses when I get them. Even the ones I put in pots permanently get buried with the grafts below the soil level right from the get go. Your roses will do fine and winter better for it.

One consideration--are you sure the potted roses are grafted? If they are, follow Seil's instructions, but if they are own root, I'd guess don't do that. Did you get them from Roses Unlimited or Chamblees, for instance? They have own-root roses (so do some other places).

Kate

Last year I planted bare root ht roses 6" deep. Some of the bare roots did not break dormancy so I replaced them with potted roses and found that the graft was at or just below the soil line. I planted these 6" under as well, leaves and all. This spring one rose was completely dead and a few others started out with some growth but died during the ups and downs of this spring. The potted roses that I planted last summer survived and are doing well. I did not protect any of the roses, but did get a heavy blanket of snow that stayed. I am in Ontario and am probably considered a zone 4 according to the US map. We had a brutally cold winter and the ones that survived were Marie Luis Marjan, Berolina, Peace, Royal William, Elina, Eliza, & Kordes Perfecta. Wild Blue Yonder was dead in the spring. Savoy Hotel and Julia Child and Hamburger Deern showed some green and growth in early spring but then died. For me the experiment continues as I try to find what is reliably hardy and disease resistant in my zone.

6" is complete overkill in your zone. Many roses will not thrive planted that deep as it is very difficult to get both water and oxygen to the root system. 2" below soil line should be fine. If your roses are mostly on Dr. Huey understock, then that likely explains your mortality rate. Get them grafted on multiflora and plant them 2-3" below the soil line and they'll be fine.

Thank you! Got 'em in, and crossing my fingers that we don't see another winter like the last!