plants that thrive in wet @ boggy ground

Perennial Lobelia Cardinal Flower is suitable , but not all varieties are totally hardy, However Lobelia syphilitica, is a fine blue flowered hardy perennial that will grow in wet or dry conditions, reaches thice the height in moist conditions.

Candlebra Primulas like P. bulleyana like it, as do Ligularias. There are several sorts, all beautiful. Rodgersia, and if you fancy a real statement - how about a Gunnera!!! I also grow Lythrum salicaria on my stream bank...you can either buy named species like 'Robert' or grow the 'wild' sort from seed.. I like them just as much as 'Robert'.

what about some ferns? cant put ant names at this time of night as i cant get to my books.

Matteuca is a wet-lover. I can't think of the second bit of its name.

I would go with Spritzhenry's list and add skunk cabbage to it.

Lobelia vedrariensis, tall, purple, stunning, Trollius cultorum 'Alabaster', very beautiful, pale flowers in spring, Osmunda regalis is a fern which likes damp soil, Rodgesia tabularis with white flowers is a favourite and perhaps strangely, I have found that Knautia 'Melton Pastels' grows very well pond side. Not sure if they would cope with being permanently wet, but might just be worth a try. Also, Eupatorium.