First off: is the area you want to plant permanently wet, or just in some seasons? (Ephemeral) Is there open water, or simply squishy ground? How big is it?

Are there trees around it? And are they evergreen, or lose their leaves?

What's growing there now?

With four children - does it need to be kidsafe? What did you have in mind?

What sort of soil is in your yard and bog-to-be?

How much sun does this area get in winter and in summer?

Do you get wildlife in your garden - deer, rabbits, and such? Do you have to factor that in to your planting plans?

Have your thought about including edibles in your plan? Cranberries and blueberries. Even brambles.

What resources so you have on the site - such as rock, timber, native plants?

If you install your plan - might it affect any neighbours? Cut off sun, or change water flows, or move visiting animals into their yard? You do have to literally think outside the boundaries because unhappy neighbours can be hard to live beside.

Hope that gives you a few leads and, if you can share that information plus your general location on the forums, this or even 'New to Gardening' ,then it makes it much easier to offer more specific suggestions for plants. You might also want to pose a few questions on 'Perennials' and 'Irises' if either of those plant groups appeals.