Answer: First of all you should probably find out if you are allowed to extend any plantings into that area. In some cases those areas are protected and in other cases they are necessary to control surface runoff during storms.
Since the area is naturally wet your best bet is to plant things that like those growing conditions. You might look at woody plants such as shrub dogwoods, aronia, summersweet clethra, deciduous hollies, willows, river birch, and red maples. You might also consider some of the perennials which prefer moist areas such as marsh marigold, Japanese iris, astilbe, hosta, Joe Pye Weed, hibiscus, bee balm, or lobelia and along the drier side perhaps Black Eyed Susans and ornamental grasses.
While you are still at the planning stage you might wish to look at a basic book or two. One I particularly like is "Gardening for Dummies" by Michael MacCaskey ISBN 1-56884-644-4. In it you will find some basic planning considerations and specifics on soil preparation. You might also wish to contact your local County Extension (678-7807) to see if they have any specific suggestions for planting such an area.
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