I have shaggy blazingstars (liatris pilosa)to trade.

Of course, you are in a much colder zone, but I think more plants are lost from poor drainage situations than actual cold. You will be surprised how much your seedlings will grow next year. If they don't overwinter their first year, it is quite possible they would not overwinter if mature, sort of survival of the fittest. If it helps any, I've started seeds in August before & planted them outside a few weeks later, most all of those, if not all, came back in the spring. We don't get nearly as cold as you, but these were pretty small seedlings when I put them in the ground. You would need to put lots of stuff on your lasagna bed, remember that it will decompose. Look up lasagna gardening & you will find lots of information. I've never done the actual lasagna bed, I mix in a bag of garden soil, manure, & peat in as well. I wanted to plant immediately & just felt better than planting in very loose stuff. Or maybe if you shred the leaves before adding to the mix, would be better, I didn't think to do that to mine. It worked fine, everything grew well, but the leaves seemed to mat down & didn't decompose as fast.

Just a suggestion - You might get takers if you say where you are located right up front here since this forum covers all of New England.

I already did. There's no response on here anymore. No active seed savers and traders. I have Rose De Berne, Black Pineapple, and Cosmonaut Volkov seeds, and there's no interest at all. Before Gardenweb was piggybacked onto Houzz, the trading forums were extremely active, with new and exciting posts every day. Now, it just seems to be collectors looking for specific things, and only will trade for specific things. Back in the day of active traders, my garden diversity compounded by 10 or more varieties because 10 plus people wanted to trade. I only got 3 responses, so far. I save seeds, and so have thousands of seeds, and no one wants them. Maybe that's what happened to the other traders, they just stopped saving seeds because they couldn't find anyone to trade with. I find it very strange, that with all the school gardens, community gardens, food forest projects, urban gardens, etc, that no one seems to save and trade seeds to increase their garden diversity at a very low cost, by trading.