I think you may be looking for Platycodon,which is commonly known as Balloon flower,Telme8..I saw some in our Garden centre only this week..If you type in 'Platycodon' in the Google search box at the top right hand side of the page,you will find lots of information,on where to buy and how to grow and care for it...Hope this helps....

If you do mean Platycodon, I've had a few of these down the years - sadly, never managed to keep them longer than a few months, but then I have to grow them in pots, maybe they prefer the ground.

We have them, blue pink, white and a lovely lilac colour.
They self seed for us as well. all except the unusual coloured one that is.

I googled P. seeds uk and found them on this link http://www.mr-fothergills.co.uk/Flower-Seed/Platycodon-Mixed-Seeds.html#.WX5FoLpFy70

Hi Telme8, how are you doing?
I've found them in packs of 3 roots from parkers mail order. I must say they did well for me in the ground for a couple of years.

Thanks ever one for your help I will follow up. A friend of ours has a big deep stone pot with Agapanthus in the middle and balloon flowers all around it is magnificent. He did not know what they were but said he dead heads them every day and they just keep coming. I was so impressed with them, so I looked them up on line to identify them and you are right with the botanical name. Thanks again. I
knew I could rely on you regulars.

Hi. If you are still looking for balloon plants I bought one in Morrisons last week. £2.
Then I found two hidden under a Geranium and a Heuchera that i planted earlier this year !