I think you are forgetting how tough roses can really be when you worry about those feeder roots.
When roses are harvested from the rose fields, generally in October in the Wasco area, they are yanked out of the ground by machines and thrown onto trucks or trailers to be hauled to the processing area. Roots are cleaned and a lot of the top growth chopped off and then they are put into cold storage to encourage dormancy.
We think the feeder roots are important, but actually, at this time of year, when all cellular activity has slowed down, they are not as vital in the colder zones because the conditions are not right for the roses to put on top growth, so once in the container, the rose has time to grow new feeder roots. In my experience, roses grow their roots first before they put on new top growth.
Putting the dry roses in water, rehydrates the canes where these roses are storing their nutrients ... I am talking about modern roses ... and the rose will use those nutrients to grow roots as soon as it is in the container.
@Paul2032 ..... those roses do look really good and I think that nursery is handling them very well. You are lucky to have such a good place near by to purchase plants. I just wish most of the nurseries would handle their plants as well.
Smiles,
Lyn