Not sure of your zone, but my elephant ears drink up a ton of water.

Cannas love moist soil, so do irises. Bananas are very thirsty, but may not be appropriate for your area.

You've come to the right place! I have the swampiest back yard of anyone I know. The ground is mushy mud, all year long. After heavy rains, there are often puddles of water for days. You have the right idea! As the vegetation develops, it sucks up more and more of that water. My "pond" is more of a "swamp" now...and it gets drier and more manageable with each passing year as the vegetation thickens.

• Bald Cypress and its relatives are the king trees of the southern swamps. They can sit in water, all year long, unlike any other tree in North America.
• Sweet Gum loves the muck! It grows like gangbusters in mushy mud.
• Black Gum and its Tupelo relatives do well, too.
• Red Maple does well.
• Loblolly Pine loves the wet.
• Wax Myrtle bushes grow like crazy in the goo.
• Button Bush will thrive in the swamp.
• River Birches are made for water.
• Water Oaks are the grand daddies of the bottom lands.

Just look for anything with "swamp" or "river" or "water" in its name. Make sure it's native to your area. Plant in November.

To the above list I'll add American beauty berries, inkberry, fringe trees, and hydrangeas (those need some shade tho).

What you have amounts to a rain garden (yes, there is such a thing!) So look for rain garden suggestions and you'll find lots more great ideas.

Oh, one more shrub--itea (Virginia sweet spire).