Crab grass produces distinctive forking inflorescences.

Do we actually have it here? I didn't think we did.

Does the average homeowner know what an "inflourescence" is?

Anyhow, the "patch" description does not sound like the word which I would use to describe crabgrass. But we do have it around here.

It pretty much did not exist in Washington County (Beaverton, Tigard, Etc.) in the 1970s to 1980s.

In 1985, is was in parts of Portland, including the University of Portland where I was working. By the 1990s, it was definitely in Washington County. And we have a few small ones in our front shrub bed right now. I weed them about every two weeks.

I did not recall seeing it at all on the country clubs I worked at in the 1980s. Pretty sure they must be seeing a bit of it now.

Link ...

Here is a link that might be useful: Crabgrass on Wikipedia

There are different kinds of clover. I really like the white clover and encourage it in my yard, but don't like the burr clover. Clover fixes nitrogen so helps to feed your lawn grasses.