Where I live Hesperis matronalis is considered an introduced invasive and is illegal to plant or transplant anywhere in the state.
I do enjoy Foxgloves though. Sometimes they reseed for me, other times they do not. I just put out more seeds if they get too thin or disappear on me for a season. That usually gets me 3 to 4 seasons without having to manually reseed.
Also, both of these plants are considered 'biennials', though sometimes they get called 'short lived perennials'. Meh...if an individual plant comes back more than one or two seasons on it's own, I'll just treat it like a perennial anyhow.
