Most of these plants are technically what I'd call 'wet meadow' plants. Any normal soil with a relative amount of moisture should work. Most can survive temporary drought and ordinary garden conditions. For example, I grow Ironweed on a dry hillside with few problems. Conversely, most handle temporary flooding well too.

Now if you if you are looking for true peat bog plants and shrubs, I'd look at things instead like leatherleaf, laborador tea, swamp azalea, and bog rosemary.

There's a nursery in NJ, Rare Find, that has many of these sorts of things, although he may not always list them in the catalogue. Evermay in Maine has a few good bog shrubs too.

Here is a link that might be useful: Rare Find