This is my first grafted rose in a long time. I used to plant them deep, and then fought with the canes that sprouted from the rootstock. If I don't bury the graft, what kind of winter protection do you give it? A scoop of potting soil, hilled up, be enough?

Bury the graft. Definitely bury the graft.

Unless the scion dies off, which IME is usually the result of not burying the graft, the only way the rootstock suckers is from budeyes on the shank. Since one of the normal procedures in budding is to remove these budeyes, good quality grafted roses should not have them. My experience with a few thousand grafted roses (don't ask) was that two produced rootstock suckers without having the scion die first from the rose being planted too high. When I've mentioned this in the past, other people who have dealt with thousands of roses agreed that it's a perfectly reasonable percentage. It does happen, but should be quite rare.

BTW, bury the graft.

Bury the graft at least 2-3 inches.

BC:)

I bury the graft on all my grafted DAs by at least 6 inches and I have never had rootstock come up and sucker.

Enjoy WS. I have 2 and love them both.