Pretty pink petticoat

I had siskiyou for years, it spread wonderfully, and flowered all summer .....then one year it vanished. Hope yours doesn't follow suit, it looks very similar, so pretty:-)

I thought I had lost it as I'd not noticed it growing through everything else. Must put a label in so I don't weed it out by mistake.

I had read that they can be invasive and they had spread so far that I was thinking it might be, then gone! I even put some in a pot, that died too:-(