I have heard it is really possible.
Although I've never done it, it can be done, Marcia. Here's a link:
Good posting from Ann.
Just like her, I have never done it, but the link sure makes it look intriging.
The potato will feed rose and assist to root the rose start. Taters have magnesium and other minerals that roses need.
Marcia: here is a video you must see!