Can anyone identify this weed and recommend how to get rid of it?

I don't know the name of the invasive grass, but to control an undesirable grass growing in a desirable grass lawn, you will not find a selective herbicide. What kills one grass will kill another. (With the exception of crab grass, which this is not).  So you will have to pull it, or spot spray it if you can find the points of rooting. . 

 

The other option is to start over, use a systemic herbicide to kill the entire turf and roots, wait for re-sprouts and kill those, then remove the dead grass layer, roto-til in copious compost and replant with the type of grass or other ground-cover you want. Or if you don't want to use herbicide, a less efficient kill with more chance of resurgence, is to dig it all out, wait for re-sprouted root and stem fragments and dig those before replanting.  

19 minutes ago, drtreelove said:

systemic herbicide to kill the entire turf and roots,

Any recommendations for an effective one that I can use to kill off the stuff growing up my back wall as I cannot easily get to the other side of the wall to cut it down and to spray/pour over stone beds to hinder growth from underneath?

 

HomePro/Thai Watsadu or the gardening market in Pattaya as stockists would be good. A picture of the label even better 

Posts #7 and 8 have photos of c

ontainers.  Ask for Ya-ka-ya (chemi kills grass) or more specific Gly-po-set. Buy a small hand held pump up sprayer and 

On 7/10/2018 at 3:25 PM, drtreelove said:

I don't know the name of the invasive grass, but to control an undesirable grass growing in a desirable grass lawn, you will not find a selective herbicide. What kills one grass will kill another. (With the exception of crab grass, which this is not).  So you will have to pull it, or spot spray it if you can find the points of rooting. . 

 

The other option is to start over, use a systemic herbicide to kill the entire turf and roots, wait for re-sprouts and kill those, then remove the dead grass layer, roto-til in copious compost and replant with the type of grass or other ground-cover you want. Or if you don't want to use herbicide, a less efficient kill with more chance of resurgence, is to dig it all out, wait for re-sprouted root and stem fragments and dig those before replanting.  

That's the way a landscaper would do it.

Depending on your soil, this might be an opportunity to add some quartz sand before rotovating. 

I see two different weeds: bermuda grass and maybe nutsedge. Bermuda grass is very difficult to get riddle. It grows by rhizomes. If you leave a little piece of its roots in the ground, it will grow back. Very common weed in the West Coast of the USA and it seems to do well in Thailand too. Some people grow it as a substitute for a lawn.