I just received my first Gunnera plant!
Now, I know they are not supposed to survive the winter in my zone,however, I do the cement leaf castings, and I figure that even if I get a few "baby" leaves this season, it will be worth it! Of course, I am still going to try to keep it over the winter. I need an opinion though-I do not have any damp areas in my yard, I was thinking of taking an old plastic pond liner, burying it in the ground, and drilling holes in it about a third of the way from the bottom, so it will hold some water, filling with soil and planting in that. How do you think that will do?

I've had Gunnera survive Cleveland winters now 2 years. The first with a blanket of leaves (no damage to the crown at all) the second without any protection (some damage but I still have the plant). The first winter I had -6F. This past winter it didn't drop below 0.

I think the key is protection AND close to the foundation.