I have been fiddling around a bit with low growing native perennials:
Two natives for dryish shadyish spot that might suit you-
Tiarella trifoliata never stops blooming
Tellima grandiflora I spent $$$ on 'Forest Frost' but it's not really better than the species.
I the jury have not yet decided about Vancouveria, which might be too enthusiastic
Potentilla var. anserina clearly was too enthusiastic
Cornus canadensis may need too much water, but is gorgeous if you can do it.
gus- Caladiums love heat, and here in Washington they often never get going as it is just too cool. Your little shade patch looks lovely.
