This is an oxalis, I reckon, and it's very difficult to eradicate. You can spray it with systemic weedkiller if it's not amongst other plants, or else dig, dig dig. That's what I have to do - I'm afraid it's an on-going task, though.

Yes, dig, dig, dig. Weve got it also.

We had some in our last garden & just pulled it up where it was in the way and left it where we didn't mind. There are worse weeds to have...

It spreads like anything if it's left, Beattie...at least, mine does! :-((

We had it in paths, so I guess being walked on gave it something to think about. We had mind your own business in the grass (I won't call it a lawn...) and were keeping an eye on the neighbour's Japanese knotweed.

Ooops! MUCH worse! :-(((((

Weed out and keep weeding out. Somehow it has overtaken a small bed of ours and we will have to dig everything up and out to eradicate.

I met the ex-neighbour a year or so after we moved and he commented on how the Japanese knotweed by the fence was regrowing now we'd gone. Funny that...

lol

We left Knotweed behind us, as well! I'm so glad it doesn't grow here.