Beginner Gardening: can anyone identify this?, 0 by Halarbour

Halarbour wrote:
recently this plant has migrated from our neighbor's backyard to ours and no-one knows what type of plant it is
the photo isnt very clear sorry but it is more purple in the leaves then green, in fact most of the time you cant even see the green i just noticed it after i took the picture
and also it flowers these white flowers but i dont know how to describe them and i dont have a picture of when it is flowering, sorry