It's hard to tell for certain from the images, but it looks like one of the threadleaf forms of Ironweed (Vernonia). It could be the cultivar 'Iron Butterfly' of Vernonia lettermannii. This species of Ironweed is not locally native, but instead wild to a very small area around Oklahoma and Arkansas. Our locally-native Ironweeds are New York Ironweed (Vernonia noveboracensis) and Broad-leaved Ironweed (Vernonia glauca), though the former is much more common and widespread than the latter. There are a couple other threadleaf-type Vernonia on the market these days what are very similar in appearance to 'Iron Butterfly', which are 'Summer Swan Song' and 'Plum Peachy'. Mature height is probably the trait that separates them (though they're certain to be overlap), though some of those might bloom a little bit earlier or later than the others.

Ironweeds can be divided (but do not require it regularly), and several references suggest this should be done in spring, just before or when the plants are breaking dormancy. We don't know how successful an attempt made now would be. Some sources say that young plants divide better than older specimens, but this is not something we have studied.

The mantis does happen to be native -- our only locally-native species, in fact, Carolina Mantis. Always nice to see!

Miri