Stonecrop rare

It is not a killable herb. Grows right on rocks. This grass grows very well. I brought this to our garden 3 years ago. Since then, the grass has settled in five places. Surprisingly .. She seems to be crawling from the place where she grows. You can walk on the grass. You can sleep on this grass. Nothing can kill this herb. Stonecrop rare grows very small. Maximum one inch. In the background is a cypress tree.