I have one of Trimmer's cultivars which used to be considered EV - Piano Man, which has done wonderfully in zone 4b. I admire a lot of his and Jane's new cultivars, but they seem to all be EV's. How do they do in the tundra?

DRAGONFLY DAWN did fine here this past winter. I do believe it made it through the winter in Vermont as well (@Aroseblush correct me if I am wrong).

I did not have WAVES OF JOY outside but I did have seedlings from DD X WOJ that were in a pot and experienced temps way below 0 with no mulch and they perked right back up when brought inside to get them growing in mid March.