Put up a fence and figure out how to drain the water so you have a useful yard or put in a pond.

Here is a link that might be useful: Propagating Perennials

I'm going to try Elephant Ears, $3 each @ Walmart.

Almost 6 years ago we planted three Nishiki willow bushes along our very moist back fence to screen us from the neighbors. They were supposed to grow to 4' x 6' or something -- in normal soil. In our soil they took off and within 2 years were screening beautifully. After 4 years I started wanting to actually cut them back a bit. They have topped out at 12' high but continue to grow outward and can get quite dense. I thin a bit every year so that the plants in front of them can get a little sun! Very hardy and lovely and fast-growing. Might be the plant for you!

Google: Salix integra ÂHakuro Nishiki for images, but remember you will only see small specimens. If I had to do it over again I would plant them a good 6-8 feet apart and at least 6' from the fence.

Good luck!

try poplar or willow

Don't use willows near septic lines. Otherwise, they're fantastic. The curly willows provide nice form and grow up instead of weeping down to the ground.

Sweet bay magnolia (magnolia virginiana) is a gorgeous semi-evergreen, fragrant small tree to about 20-30 ft high. We love ours.

Itea virginiana is a native shrub with sprays of white sparkling flowers in late May and gorgeous red fall color. Deciduous. The "original" is tall enough to screen, but there are new small varieties, too.

Here is a link that might be useful: my gardening blog

I agree with bullthistle. Put in a fence. Then put in a bog garden!

Look at Buttonbush--Cephalanthus occidentalis. I believe there's a cultivar now, possibly called'Sputnik'.