Hi Chris, good to see you.
A really good Comfrey cultivar for you is
Russian Comfrey (Symphytum x uplandicum 'Bocking 14') because it is sterile and doesn't set seed. It's the only comfrey we grow around here and does great for us, although it does tend to struggle a bit in the very hottest parts of the summer.
I know you are looking for a local source of it, but if you can't find it: it reasonably priced at Horizon Herbs:
https://www.horizonherbs.com/p...
I ordered mine from them and was happy with it.