Thanks for writing in! Are you interested in adding some natives perennials? You might want to consider some ferns, which will need some moisture in their soil until established, but then they are quite adaptable. Eastern Wood Fern, Dryopteris marginalis, forms attractive & tidy clumps, and would pair nicely with Virginia Bluebells Mertensia virginica, which blooms beautifully in the spring and then goes dormant as the Wood Ferns would take the center stage.Adding another native or two would give still more diversity & interest. Plus, some fall bloomers would add value! 

Another nice fern, Christmas Fern, Polystichum acrostichoides, is evergreen, but still coexists with spring ephemerals, just as they do in the wild.. Both ferns are short enough to blend with a formal look, or you could go with taller ferns for a wilder woodsy look. 

https://bluewaterbaltimore.org/blog/four-ferns-for-dry-places/#:~:text=Dryopteris%20marginalis%20(eastern%20wood%20fern,are%20interplanting%20with%20other%20perennials.

If you could provide more watering, another option would be Jewelweed, Impatiens capensis, with its lush foliage and profuse bright orange blossoms. It is an annual, but happily reseeds itself in favorable conditions. It is not available at big box stores, so Jewelweed will make your garden exceptional. Or if the area gets a little bit of sun, Woodland Stonecrop, Sedum ternatum, forms a low evergreen mat and blooms in the spring.
These are just a few examples, for more ideas: https://mgnv.org/plants/native-plants/ground-cover/chrysogonum-virginianum/

Please keep us posted!

Kate