Where you live, I wouldn't chance it - best kept out of the worst of the weather over winter I think. It's fully hardy once its established though, as you probably know, can be pretty invasive in fact. If its a small plant, it may not have formed any tubers yet, may just be ordinary roots - if it had formed a tuber, more likely to survive cold weather. If you're not worried about whether this one survives or not, chance it and plant it in a suitable spot.

Thank you. You are probably right - I do not think it will have formed tubers yet. I definitely want to be sure it survives, even though I know it can be invasive. Do you think it will be OK over the winter in a pot, in a sheltered pot?

Meant 'sheltered spot'!

Hi Mccubbin welcome to Goy-- hope you have time for a look around--

If you can stand a sheet of glass or something in front, that would be a big help - and bubble wrap the pot, or put bubble wrap inside a bigger pot and push the pot with the plant in inside that...

Welcome to GoY! I read about this plant being invasive, but I wish mine would pay attention and invade a little more than it ever does. I've been doing what the books say and it just puts up a few straggly shoots, then sulks.

Mine did that too, Ojibway. It only lasted three years and then gave up the ghost. It hasn't reappeared this year. :-(