Please help to identify this type of weed

[breakpoint]

I have St. Augustine grass and so are my neighbors. It all started with a

small area. After mowing the lawn, it took over in the past few weeks. All

my neighbors have no problem. I live in Southern California, United States.

I took samples to a few nursery and they have not clue. Please help.

Attached is the link to those weeds pictures:

https://picasaweb.google.com/breakpoint ... aD3w-eMgwE#

[cynthia_h]

It may be johnsongrass: https://en.wikipedia.org/wiki/Johnson_grass. Pull it up by the roots when you can, before it goes to seed; a trowel or an asparagus knife will help dislodge the root mass. The plant spreads both by roots and by seeds.

Boiling water and/or horticultural-strength vinegar may also help; don't use Roundup, as some regions have reported glyphosate-resistant johnsongrass.

Cynthia H.
Sunset Zone 17, USDA Zone 9

[Kisal]

It looks more like annual bluegrass (Poa annua) to me, but I'm no grass pro. Did you spread anything on your lawn recently, or reseed? Annual bluegrass is very common in seed mixtures.

This is a website I find useful when trying to ID weeds:

https://www.ipm.ucdavis.edu/PMG/weeds_intro.html

[dirtyfingers]

My son's St. Augustine lawn has the same type weed/foreign grass growing in it. Looks like the same thing with the purplish roots. I took a sample to the local nursery and they could not identify it so we assume it is some type of grass from a neighboring yard. I pretty much just bent over and dug each one up individually and now there are a lot less of them. They do multiple very quickly so you just have to stay on top of them. I tried the chemical warfare routine which proved to be useless.

Good luck.