I am looking at getting a bit more greenery in my pond, and have looked at making a mock bog in my pond. The Gunnera manicata would look great and would help shade the pond a bit more in the middle of the day, but, with wet feet, how do you think it would stand up to a day full of sun? The thing is I've already got it and have it in the pond but am keeping it in the shade until it gets used to being in the water. Any tips would be great, thanks. Also, what about overwintering it in the water?

I don't know much about Gunnera. I looked it up. It likes moist but not wet soil. I don't know if it could adapt to being in the pond. Perhaps it could in the shallows. It's a tropical plant so if you live in an area that gets winters, it should come inside if you want to try to keep it alive. The plant does not naturally grow in sunny areas so it may dry up if it's in full sun. Here's a link I found with good information:
http://www.worldplants.com/gunnera.htm

Well, I put down a few courses of bricks and moved the plant. The pot is now only half submerged in the pond, and is in a spot where it gets a lot of shade from the overhanging plum tree. I had to cut off all the stocks except for the smallest, and it has perked right back up again. Once it grows a bit more and the roots start seeping out of the pot, I think I may try to move it to a shallow space in a bit more sun. The idea with this plant was to shade the pond after all.

I keep gunnera as a marginal. It's a beautiful plant but like Robyn said, it is tropical.