Hmmm...
How much shade do you get?
What kind of clay?
The red clay hills kind or the real sticky kind?
Have you tried Opuntia cacti?
Grows very well here... there's the small kind that is everywhere, and the giant kind that is easily had.... just grab a pad off a bush or wait till a real cold spell, and then grab a section that relaxed to the point of laying on the ground...
I guess that you could plant Kniphofia...
I'd rather plant bright colours... like miss huff lantana, and malvaviscus arboreus and ruellia elegans and hot lips salvia microphylla... which all do fine (in our area) with no water, and should do fine in clay as well as sand.
Also... cannas and flowering gingers... which love clay soils...
