Ask Mr. Smarty Plants

Since you bought the plant at a local nursery and very few nurseries carry native plants, I suspect it isn't a plant native to North America.   Our focus and expertise here at the Wildflower Center are with plants native to North America so we aren't going to be a help with non-native cultivars.  However, I did look for some native plants that showed a match to at least some of the features you mentioned.  Take a look at these:

Actaea pachypoda (White baneberry) and here are photos and more information from Southeastern Flora.

Aruncus dioicus (Bride's feathers) and here are photos and more information from Southeastern Flora.

Baccharis halimifolia (Groundseltree) and here are photos and more information from Southeastern Flora.

Fothergilla gardenii (Dwarf witchalder) and here are photos and more information from Southeastern Flora.

Mitella diphylla (Twoleaf miterwort) and here are photos and more information from Southeastern Flora and still more photos from Missouri Plants.

Phacelia fimbriata (Fringed phacelia) and here are photos and more information from Southeastern Flora.

Silene stellata (Starry campion) and here are photos and more information from Southeastern Flora.

You should do a search yourself in the Southeastern Flora database using flower color for your search.

You should also do a COMBINATION SEARCH in our Native Plant Database selecting "Florida" from the Select State or Province option and "white" under Bloom Color.  You can also limit the search by Habit (general appearance), Size Characteristics, etc.

If none of the plants above are your plant and you don't find it in one of the searches suggested, you can visit our Plant Identification page to find links to plant identification forums that will accept photos for identification.