I don't have much in the way of stats for Jean Swann, only that it is one of the few doubles that will remain in my garden as I downsize. I purchased it in 2009 and it has been in the same spot since then. It really, really needs to be divided because this year it was not as pretty as other years.
Picture from 2011 of bud count and branching.
Garden shot from 2017 - registered at 32 inches and I believe it gets about that tall in my garden.
2021 - I counted between 20-25 fans this year and they are packed tight so the foliage looks very ratty. It blooms between mid-late June and mid-late July in my zone 6b garden.
I've never noticed rust on Jean Swann, even though the database shows that it is susceptible.
