These three species are very easy to grow, but also a little rare in rock gardens.
My favorite combo.
Erigeron carringtoniae is adaptable, long-lived for me, quick from seed, and a punk with dyed pink hair. I think John Stireman says this is his favorite fleabane. (There are about 200 species)
That's like if Paul McCartney told you what his favorite blues album is.
Will you heed the tastes of a man who has grown more species of Erigernon than God?
My favorite Prickly-Thrift is Acantholimon puburulum ssp. longiscapum. Nothing pollinates it, so I have to take cuttings. The decent-sized flowers do not open flat, but they are held on scapes.
I'm a sucker for scapes.
It's softball sized.
You've probably weeded Gallium odoratum from some garden or another until you could scream. Most of us have. But this relative- alpine woodruff - is a slowly widening clump of easy bliss.
You can even divide it. Easily. Not true of most great bun and cushion rock plants. You won't be able to find it under the flowers. Put it on your list to find for 2020. If you can't find it, go with Asperula gussonii. I actually like it better.