Last summer I got three near-death Seibel 13053 grapevines for free. I managed to keep them alive and they are now pretty healthy looking. I only know they are supposed to be virus-free and stand-alone in the state I got them.
They look like they might have been grafted because they have tiny buds around the joints but it's hard to tell because their trunks were pencil-wide when I got them and they look nothing like the Cabernet Sauvignon vines I bought which are clearly grafted to obviously different rootstock.
May have been practice plants? My bad for not asking.
Problem is I was fairly successful rooting the cuttings I took last winter and now I have three additional 13053 grapevines growing on their own roots and I wonder if they are doomed given that it's pretty likely they get exposed to phylloxera at some point, this being a grape growing region.
I know that mr Seibel was trying to get phylloxera-resistant hybrids and that one of its ancestors is a rootstock variety but my Google-fu has been unable to confirm its resistance or lack thereof to the evil bugs.