Ask Mr. Smarty Plants

First, let us refer you to a previous Mr. Smarty Plants answer on dealing with clay soils. Follow the links in it for suggestions on dealing with that and for perennials that will grow in it. The person that asked that question lives in North Carolina, but most if not all of the plants will also flourish here. You can follow the plant links and read the webpages about each plant.

Now, as to your question about perennials in standing water. The water remains after a rain because your soil IS clay, and/or because of the elevation of the plant. Frankly, no plant besides those that grow in swampy ground can stand having its roots under water for very long. Very simply, the plant will drown. And if you select plants for swamps, what is going to happen to those plants when our usual drought conditions come back and the soil is very dry? We advise you to give some attention to the soil before you start buying plants. Compost or some other organic material, worked into the soil, should help both to raise the level of the soil and to reduce compaction in the clay. You already know the areas where water stands-how about some raised beds of some sort? They don't need to be elaborate, just an area where the soil will drain more easily and has somewhere to drain to. This Ohio State University Extension Fact Sheet on raised beds has some excellent suggestions.