They will almost certainly cross pollinate. Doubles gradually revert towards their wild ancestors. To collect the seed wait until the flower is withered and monitor it closely. Just remove the head when it is dry and rub between your fingers. The seeds will come apart.

Thanks, I guess its not really worth the bother, if its going to cross pollinate and revert to singles. It is so pretty though, any chance it might winter over, if I keep deadheading? I know some nurseries call them perennials, when they are really biennials, but this one is really pretty and I'd love to have more like it. I've never had them winter over, but maybe with some protection, do you think I could winter it over, and maybe divide it next spring, as I would other perennials?

I don't know about the cultivated versions but the wild Bellis perennis is totally hardy and will withstand even the coldest winter. They are one of our commonest wild flowers and thrive in lawns where they withstand weekly mowing and bounce right back. Considered a weed by lawn people, although I love them.

Hi Flora. In zone 5 NY, bellis doesn't overwinter. I plant it every spring and it doesn't reseed or come back. I even grew it from seed one year and it didn't reseed or winter over. I wish sometimes that I had the climate of the UK!

Hpny2...save the seed and give it a try. Sometimes you can be surprised with experiments.