I didn't use the potato method, but one spring I pruned my daughter's rose bushes, then used the cuttings stuck in the ground to help keep her dogs from walking through a newly planted perennial bed. Guess what? At least 4 of those cuttings rooted! I'm crediting that we had a microsprinkler watering the new bed every day, and had a run of cool weather as well. Still, amazing in that terrible clay soil, and low humidity.
Sadly, they were next to a walkway so the rose bushes would have been grabbing everyone's legs if we'd left them. So we tried to transplant them, probably too soon, and I don't know if any of them survived. They would have been 'own root' bushes of hybrid teas so probably very wimpy in any case.
