Could be Lychnis coronaria.

I agree,it's Lychnis.A hardy plant ,which will self seed ,or can be split.I have had the deep pink variety for years,but I believe it's also available in white .

Yes, I agree. It's a plant that once you have it, you will always have it. But it is a stunning Magenta colour and fills up spaces in beds without being invasive. Doesn't seem to mind soil type but prefers sun. Growing beautifully in my path! I also have the white one.

I agree and it does indeed come in a white form and a sterile [? ] white and pink form.

Thanks everyone .This has great members always able to know answers Thanks

Nice to hear from you again,Pammie :o)