According to the BONAP atlas (http://bonap.net/NAPA/TaxonMap...) Y. flaccida is native to Kentucky. However, my copy of Jones' Flora of Kentucky shows it and [Y. filamentosa] are not natives but regular escapes here.
Always looking for interesting plants for pollinators and food! Bonus points for highly, and pleasantly scented plants.
"Si hortum in bibliotheca habes, nihil deerit." [“If you have a garden and a library, you have everything you need.”] -- Marcus Tullius Cicero in Ad Familiares IX, 4, to Varro. 46 BCE