Bought our house last year. All I remember about these is that these originally looked like grass and I was shocked when the flowers burst through such fine pointed grass. It seems to me (given my limited memory) that the old owner cut these back in the fall. We did not trim back in the fall. So now I have no idea how to keep them from spreading further.
Ps these are actually two different patches. And yes, I know that they look like grass. They're not though.