Red Admiral host plant: mint family??

[Sheri Moreau]

Rumor hath it that there is a plant in the mint family (possibly a hyssop?)
that serves as a host plant for Red Admirals. I've been unable to identify
such a plant. Can anyone help out? 

Also, supposedly Red Admiral larvae will eat hops leaves, however
experiments with several varieties of hops this summer have been fruitless.
Is there a particular variety they prefer (bad as some beer lovers I know..!).

Ideally, I'm trying to come up with a non-stinging plant that is easy for
teachers to raise in elementary school butterfly gardens. Baby's Tears
(Urtica ssp), while non-stinging, can be finicky.

TIA!  Sheri (webmistress at mty.com)