I planted some balloon flowers several years ago. Though they don’t always come back, in general they will in Atlanta at least. Mom has some by her mailbox that have done great and Susan planted some at her house that have come back strong this year. Unfortunately I had some mums and lamb’s ear that overtook where I planted my balloon flowers, so they have gone away for the most part. But I got a couple of stalks that came up this year (the mum having obligingly died, and therefore no longer in the way) and I noticed they were a perfect example of why they are called balloon flowers. On the left is one that is puffed up and the other has already burst open. They are also called by their scientific name platycodon (or platycodon grandiflorus) and Chinese bellflower (on wikipedia).