The taxonomy of Antennarias is an absolute nightmare, witness the near complete lack of agreement between ITIS and the Catalog of Life, and the incredible lists of synonyms for many species. It's likely that there are no (or very few) distinct species in the genus, just an endless variety of local ecotypes that bleed imperceptibly into each other.
I'd bet money that Antennaria tomentosa is a name Bluestone made up to describe a clone they selected due to distinctively wooly leaves (tomentose means "covered with densely matted woolly hairs"). It's not an unusual thing for nurseries to do, and pretty understandable given the confusion that surrounds this genus.
