Not sure about that particular form of Platycodon grandiflora, but the blue ones we have in our garden seed all over the place. Now the pink and white forms do not seem to produce new baby plants.
I have a baby balloon flower growing about 20 feet from the only other one on my whole road. How would it have got there? I have never planted any seeds either. Barb in Pa.
Are they meant to be dead-headed? I planted a couple of the blue variety this spring, they flowered, I dead-headed them and no flowers ever came back =( Maybe they weren't getting enough sun? I had some in my old place and they grew and flowered all summer.
Toadie--Are they young plants? Maybe they just need another year or two to gather steam. I grow minature balloon flowers and they do a good job os self-sowing. My regular sized ones don't though!?!