Lisa, I know little to nothing about growing these plants. I wintersowed a jug of hardy semp seeds this year, my first attempt with them. They're still tiny. But I do know that they need sharp-drainage in soil mix. Repotting your plants with different soil might make all the difference. Folks here seem to use a gritty mix with lots of gravel and sand type material. But one of the experts here could suggest a soil better than I. I'm a novice.
When I looked at your photo my thought was "too wet".
Karen
