The following plants will grow in the shade and are all less than 3 feet tall or can be maintained at that height by pruning. All should do well in clay soil. I found these plants by doing a COMBINATION SEARCH in our Native Plant Database. I chose "Virginia" from the Select State or Province slot, "Shade" from Light Requirement and "0-1 ft.", "1-3 ft." and"3-6 ft." from size characteristics. You can do the same search to see more possibilities for plants. Be sure the read the entries under GROWING CONDITIONS on each species' page, especially the Soil Description, to be sure the growing conditions meet your site's characteristics.
Coreopsis lanceolata (Lanceleaf coreopsis) is perennial with evergreen foliage and blooms April, May and June.
Phlox divaricata (Wild blue phlox) is perennial with evergreen foliage and blooms March, April and May.
Symphoricarpos orbiculatus (Coralberry) may grow a little taller than you like, but it can be pruned to keep it low. It does well in clay and full shade. It has purple berries that persist into winter. Here is more information from Missouri Botanical Garden and Texas Gardening Info.
Chasmanthium latifolium (Inland sea oats) grows very well in shade and part shade and clay soil. The dried seeds are attractive into the winter and can be removed in the spring when the new green leaves begin to form. Here's more information from Nadia's Backyard.