Ask Mr. Smarty Plants

Mr Smarty Plants’ normal approach is to point out the “Recommended Species” list and that it can be searched for plants which prefer specific conditions such as “Full Sun” and Soil Moisture: “Wet-Saturated”.

For Arkansas, this yielded the following list of shrubs: Lobelia siphilitica (Great blue lobelia), Hibiscus moscheutos (Crimsoneyed rosemallow), Penstemon digitalis (Mississippi penstemon), Lobelia cardinalis (Cardinal flower), Eupatoriadelphus fistulosus (Trumpetweed), and Silphium terebinthinaceum (Prairie rosinweed).  This should be a good starting list, but also consider the soil conditions you have versus their preferences and any other aspects that may be important to you.  There were also a number of trees suggested that can tolerate these conditions, but it didn’t sound like that was your question.

 I also found a few questions that were similar to yours; you may want to review these answers for additional insight into what you may want to do.  This question considers a similar situation in Kansas.  This one features both native grasses and refers a how-to article on water gardening. Another question discusses a pond in Missouri, and this one is also from Missouri, but focuses on smaller plants so that they can be fished over!

Finally, it's always possible that you can find expert advice at the local chapter of the Arkansas Native Plant Society or at the Carroll County Extension Office.  Another possibility is the Northwest Arkansas Koi and Watergarden Society.  I found contact information here.The Extension Office may be particularly helpful to you as in the same search I found two documents on rainwater gardens [a near relative to what you are doing], and on the use of native plants in rainwater gardens!