|I live in Mass & have a corner space in front of my house that is bare & shaped like a piece of pie (12' @ curve, 109|
|To be on the safe side I'd choose sun loving perennials that tolerate wet soils. This way you'll cover most of the bases. Generally we plant in groups, with the lower growing plants in the front of the bed and the taller ones in the back. Or, if you can see the bed from all angles, plant the tallest plants in the center and the lower growing plants along the perimeter. Here are a few suggestions. You'll need to research each to determine their mature heights or you can just read the plant tags on the plants you'd like to include in the bed. Here are a few to choose from:
Aconitum (Monkshood), Hibiscus (Rose Mallow), Actaea (Bugbane), Isolepsis (Scirpus) (Fiber Optic Grass), Alchemilla (Lady?s Mantle), Matteuccia struthiopteris (Ostrich Fern), Alocasia (Elephant Ear), Monarda (Bee Balm), Aruncus (Goatsbeard), Mimulus (Monkey Flower), Asclepias incarnate (Swamp Milkweed), Miscanthus(some varieties) (Maiden Grass), Aster novae-angliae (New England Aster), Molinia caerulea (Purple Moor Grass), Astilbe, Myosotis (Forget Me Not), Panicum virgatum (Switch Grass), Bergenia, Phalaris arundinacea (Ribbon Grass), Physostegia (Obedient Plant), Rodgersia (Rodger?s Flower), Gunnera (Dinosaur Food), Sisyrinchium californicum (Yellow Eyed Grass), Hosta (Plantain Lily), Thalictrum (Meadow Sweet), Ligularia, Tiarella (Foam Flower), Lysimachia (Loosestrife), Tradescantia virginiana (Spiderwort), Helenium autumnale (Helen?s Flower), Trollius (Globe Flower), Helianthus angustifolia (Swamp Sunflower), Zantedeschia (Common Calla), Arenaria (Corsican Sandwort), Lysimachia (Creeping Jenny), Galium (Sweet Woodruff, ) Mentha (Corsican Mint), Houttuyuna (Chameleon Plant), Potentilla (Spring Cinquefoil), Laurentia (Blue Star Creeper), Vinca minor (Dwarf Vinca).
Another suggestion - you can install a curtain drain to redirect the excess water.
Best wishes with your garden.