All are native to humid climates, including eastern US. None are drought tolerant. The popular Japanese, Korean and tall stewartias are all rather large-growing in time, penetrating the medium-sized tree category where successful enough. E.H. Wilson once took a photo of a tall stewartia in Japan that was huge.

If you want to try one I would try the Korean as some sources say it might be hardier and plant it like you would a Cornus Florida. Moisure retentive soil and partial shade. I have plant 5 in the Cincinnati area and non have thrived. In fact I can't think of a nice stewartia I have seen locally.

Something like Cercis Canadensis 'Little Woody' would likely be much easier to grow.

David

A few years ago while vacationing in NC I happened to pass by the native S. malacodendron while in flower. Beautiful! This one was more shrub-like, but could probably be fashioned into a nice little tree. Native to the SE US, as far north as Virginia. Here's a couple of pics of the malacodendron at the NC arb in Asheville.

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Here is a link that might be useful: Woodlanders

>some sources say it might be hardier
Stewartia pseudocamellia is certainly hardy in DC - it's rated to zone 5. I have 4 up here on Cape Cod, in zone 6 or 7 - our summers are much less hot and humid that yours, but I've never heard about a problem with heat. Although these are not considered particularly drought-tolerant, mine get little supplemental water after the first year, and do well. They are beautiful trees.