Anyone know what this is please?

[On the Moors]

This white plant has been in the patio tubs for the last three years. It will be coming out soon as the wooded tubs have rotted and the plants are getting too big. They look great but we cannot find out what they are called. Can anyone put a name to them please?

 

[Apple]

Common names, Dusty miller silver ragwort. Centaurea cineraria

 

[On the Moors]

Thanks Apple, that really had us puzzled. OH isn't often unable to name a plant but this one had her stumped. I seem to recall that it was quite small a couple of years ago but it certainly took off this year - must have been all that rain!