Some sources indicate Petite Negri is the same as Violet de Bordeaux. Is your Petite Negri (listed as zone 7-9) hardier than your Violet de Bordeaux (listed as zone 7B-9)?
I'm in zone 7, but not 7B. Would Petite Negri be ok in a container on an elevated deck or would it be best to plant it in the ground? It would get more sun in the container than the in-ground location, which is a partly shaded hill bordered by a wooden fence.