I grew three species of Townsendia from NARGS seed source..all ended up as this mystery Erigeron! Is it E. leiomeris?
I realize this photo is not terribly useful for ID purposes, but this is what I grew as E. leiomerus from the seedex years ago (with this particular plant self-seeding some distance from the trough in which it was originally planted):
Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm
Certainly looks like yours...I'll call it leiomerus until told otherwise!
St. John's, Newfoundland, Canada
1800 mm precipitation per year
I don't think it's E. leiomerus. When I started gardening in the late 1990s, I grew an Erigeron that looked exactly like the one you have pictured. I'm going to go through my records and find out what it was called back then. It is not a recognized name, but it was beautiful, albeit short lived.
As you know with Erigerons, the leaf is the key to identifying most of them. I'll keep you apprised, unless of course one of our real experts comes along with the correct answer, potentially making a fool of me and identifying it as E. leiomerus
Peter George, Petersham, MA (north central MA, close to the NH/VT borders), zones 5b and 6 around the property.