Iris Cohen wrote:

Interesting. If you mean that little one with yellow flowers

Noone I asked can remember seeing this oxalis here before (eg. my
grandma). It spread the last, let's say 10 years across all gardens and
places. If you don't fight it, your lawn will be ripped off to pieces.
But it also spreads in borders and other places, esp. along roads and
places typical for other plants here. The leafs are always quite red and
roots are up to 15cm. It is highly competitive against ivy (hedera
helix), plantains and dandelion (taraxacum officinalis). I saw the first
on in my garden several years ago. It was nice looking and had those
tiny little yellow blossoms....... well.. if I knew... *sigh*