By totally shaded do you mean it doesn't get any sun?
There are lots of plants that are happy in all day shade. Hostas for one as Lesa said.
thinking...thinking...thinking...
Well here's just a short list of some that I grow. (We're in different zones but these should all work where you are.)
perrenials:
ferns
hellebore (lenten rose)
bergenia
fillipendula( Theres two types I have, "Queen of the Prairie" which is about 4' tall and meadowsweet which only gets about 18")
thalictrum (meadow rue - it's my favorite, gets about 6' tall but is very airy)
astilbe
persicaria (different kinds of these, I prefer the persicaria virginianum
"Painters Palette", it has a pink, green and white varigated leaf)
Then of course there's the ubiquitous shrubs, like rhodies, & azaleas (they probably need some sun).
I grow Clethra in mostly shade (clethra alnifolia, blooms late summer, smells wonderful)
Grasses like lesa said, Japanese forest grass is a pretty one....
Sorry for the long post.. I got a bit excited...
edited to add- I love your mule!