Frances,
Grow it in the ground and mulch it real good every winter.
That wisteria isn't the extremely invasive type like the asian wisterias, there is no need to grow it in a pot.
Cut it down nice and hard where you live around Saint Patty's Day.
That wisteria was bred for the cold.
But it will never be the most beautiful wisteria if you keep it in a pot all the time.
I am having a hard time getting mine to grow at all, and I have had it for 2 years now.
Good Luck!

I've grown 'Blue Moon' for about 4 years now. It's amazing... so winter hardy. I have 3 growing over a couple of arbor benches. I have another one in a pot, buried in the ground, waiting for my neighbor to prepare a place for it. The one in the pot does OK, but does not grow or bloom like the ones in the ground. If you want it to bloom well, I would recommend that you plant it in the ground. If you don't care about fewer blossoms, and want it on a deck or something, go for it!