Gee, this is interesting. About 4 years ago I built three small, shallow bogs with tough plastic sheets. I dug trenches about 2 feet deep. I also punched holes about 12 inches from the bottom. I then filled them with a peat and soil mixture. Now this worked well for about two years but then invasive plants started growing. I'm sure the sheets have been punctured and the water no longer collects. Your photos have spurred me onto redig the holes(deeper) and not punch holes in the sheeting. When working the bogs provided most interesting plants. Also this time I shall add sand.R squared

Thank you R2. I drilled holes at about 6 in. intervals and about 3 or 4 inches from the top lip. I'm getting really jacked to start populating it. My only fear at this point is the deer. They are just savage eaters in this part of the world. Even stuff everyone says they avoid like rhodo's, azelea, hosta....gone! If they munch my bog plants I'm just going to be crushed.
Think I should transplant some skunk cabbage or ferns to the perimeter area to nice it up?