Isn't Purple Dome just an extra nice selection of the species? It really shouldn't matter to the butterflies, I've grown several types of New England Aster over the years, and they were all treated the same. When it comes to composites my personal rule is no double flowers since the petals often block insects from reaching the nectar.

I have a couple purple dome and they're covered with blooms and butterflies...

I have an abundance of wild asters around plus several cultivars. I don't notice any difference in attractivness to butterflies or birds. There must be insects on the cultivars because I have seen warblers and chickadees gleaning from them

Thanks for the responses. I feel reassured in my affection for purple dome.

Last summer a number of my aster 'purple dome' were much taller than the 18" they usually grow to. The color also seemed to have more magenta in them than the deep purple they had been in the past. Do these revert to whatever they were hybridized with? Am not sure if I should rip these out & replace them or if last year was an aboration. Has anyone else had this experience?

tc