Annette, as long as the diseased plant was completely removed and no roots remain that could grow into a new plant, it is safe to grow a rose in that spot. As for how long to wait, I think it depends on how confident you are that you didn't leave any pieces behind. I like to wait a year.
Lyn, the only heavily thorned canes I noticed ended up being RRD. I always started out removing affected canes and waiting. In all but one instance, symptoms showed up on other canes.
