No, it's not poisonous - its Lamium, commonly known as deadnettle because its leaves look a little like nettles, but they don't have stings. Tends to pop up by itself, useful ground cover, particularly in shade.

Yes Lamium, I agree. Seeds itself very easily too. Good ground cover especially in rough places where not alot else grows.There are other varieties available too.

I bought Lamium last year as a plug. Did not know it was native ans self seeds. Still it is a lovely plant at the side of one of my borders.

I still buy Lamium, Kildermorie - but usually L. 'White Nancy', one of my favourites, don't think any of my clients' gardens went without one, lol!

I too have that popping up everywhere, all i've been doing is digging it up every so often