Good afternoon!! I have grown this from seed given too me by a friend and have no idea what it is although it germinated easily and is pretty so i will definatley collect more seed and try again next year!
Looks like a mallow Reed. Lavatera is it's posh name
They sometimes succumb to frost but -as you've found -they're easy from seed so you can grow lots more!
They self seed and are prone to try and take over.
Lovely that you got a white one See pink growing in the wild quite often but not white
Yes Mallow it is!! knew i recognised it but the white threw me. thank you!!