I grew some from seed last winter. They came up easily but now that they're blooming I'm underwhelmed. They just don't look as showy as some others I saw for sale last year, the leaves don't seem as silver. I can't say for sure what would work best for you, I had the seeds in paper towels in the fridge for a few weeks then planted them, you could just plant them as soon as the seed heads start to dry, or winter sow, or spring sow..... or just divide in spring, that's probably the easiest! Here's mine. I don't have a bigger picture, this was more an attempt at a bug shot.

Maufie, just be sure to try just a little bit at a time like maybe 1mmx1mm piece and wait a few hours or a day to see if you have any reactions to it (vomiting, diarrhea, hallucinations, anaphylaxis, etc). Then try a little bit bigger piece each time, waiting in between each time you increase the amount you try. This is a good rule to follow anytime you try something that you haven't tried before. It will probably be fine, but each person reacts differently to different plant compounds.

All I can say is be patient. I've never sown them personally, although in some of our prairie plantings, regular mountain mint is a common component. So I know it works. I think you were right to dormant seed them. That's how all of our prairie plantings get done. Beyond that, I can't really offer anything. +om

Might be a good question for the Garden Clinic forum, btw. I thought I would mention that one plant I have with similar symptoms is Pediomelum tenuiflorum, slimflower scurfpea. It's pretty tiny, surrounded by grasses and not getting much sunlight. Curiously, I have slender mountain mint about six feet away from it and it is flourishing this year, no sign of trouble. Both were planted in spring 2014 from seed. The slender mountain mint is a great plant. I like to think that it's attracting beneficial insects and maybe helping to keep aphids down on the milkweeds planted nearby, but I've got no real proof of that. It really buzzes with activity when it's in flower.