As always, great info Todd! Do you have any data around the length of bloom time on these plants? I'm particularly interested in the A. clavennae, which appears it could be similar to a white 'Moonbeam' or threadleaf coreopsis. Thanks!
In the lower part of Kentucky they bloom at the end of May and on through June - and by the middle of July coming to the end of their blooming season. It is all too short for such a pretty flower, but all pereinnals have a short bloom season don't they?. That is why we plant those marigolds, and zinnas in amongest our gardens.
In lower Alaska, Anchorage, they start up in July and bloom to freeze up in late Sept. I have "The Pearl" and it blooms like crazy although I need to put is somewhere where something hides it's knees. About 20-24" tall. Spreads very easily too.