What happens when you make a hole, does water seep in? Too much moisture can lead to crown rot.

You could plant the clematis in wine barrel halves. There are sturdy plastic, realist looking half barrels available. I saw one at home depot that looked really nice. You won't have to worry about it rotting, and you could plant around them with plants that thrive in wet soils.

I didn't check to see if water would soak in or not. We've gotten about 4in of rain in the last 10 days, and it hasn't been particularly sunny, so things are a little extra soggy right now. Crown rot is exactly why I am asking questions!

I like the half-barrel idea. I think they would look really nice too. The only problem I see with those is that they cost $25+ dollars each around here and we can't afford that. It would be nice if I could have something that could sit there permanently. I forgot to post that this is by the road, behind the sign for the camp we are living are right now, so low maintenance is good.

The native Clematis crispa is also known as the swamp or marsh clematis that would work. I personally find it to be very attractive & purchased one locally last summer. I planted it at the base of my water fountain knowing it can take quite a bit of water. If you google it you can find pictures & more info.

You could build boxes similar in size, about 2'x2' out of scraps of pressure treated wood. Line the sides with a thicker plastic, like plastic sheeting or whatever you can find, so the soil and water don't leak out of the gaps in the sides. Just make sure water can drain out of the bottom. Adding little squares of scrap wood to each bottom corner for feet would allow water to drain easily.