Blooms will tell for sure but the foliage reminds me a lot of Tricyrtis (Toad Lily), for comparison, click to enlarge the third photo here: http://www.onlineplantguide.co...

And, a couple of photo's from the ATP database:

Most Tricyrtis I have seen have a thin stem, these plants look to have a thick stem. There is one which looks about right though, Tricyrtis formosana .. and the photos taken were in Georgia State Botanical Garden .

http://www.discoverlife.org/mp...

(you might have to persist with the link, it sometimes says page can't be displayed.)

http://www.discoverlife.org/mp...

A few photo's in the database: Toad Lily (Tricyrtis formosana)