Probably, but sometimes the parentage isn't disclosed, so it's not an easy way to determine future vigor. Besides, even a rose that does well on its own roots could possibly do better if it were grafted. Hybrid musks are rarely grafted these days because it's deemed unnecessary, for example, but I have a few duplicate hybrid musks of both types and the difference is quite visible. My grafted Penelope and Sally Holmes roses are easily three times the size of my own-root Penelope and Sally Holmes, although both types have been growing in my garden for many years, so the own-root roses theoretically should have caught up with the grafted ones by now if the claims of the own-root nurseries were to be taken at face value. It's just another reason that I won't buy any more own-root roses unless I really, really want the rose and I can't find it in grafted form.
