Dallisgrass

Daniel Gill  |  6/25/2015 1:30:56 AM

St. Augustine grass

Photo By: Langlois, Page

Dallisgrass

Photo By: Langlois, Page

My friend Chris mentioned that you might be able to help identify a weed in my lawn and the best way to address it.

The first picture is of the unaffected lawn and the second picture is a shot of the troublesome weed/grass.
These appear to be coming up as individual clumps, but do seem to be concentrated around one area of the yard.

I typically just apply Scott's Bonus S each spring to get rid of the dollarweed.

Not sure if this is relevant, but I live in Metairie and do have 2 large dogs that frequent the yard.

Thanks for the assistance!

- Mike C.


Your grass is St. Augustine and the weed is definitely dallisgrass. Unfortunately, there are no herbicides that will selectively take dallisgrass out of a St. Augustine lawn. So, you have two options.

1) Whenever and wherever you see this weed, promptly dig it out. Dallisgrass has the ability to produce tremendous numbers of viable seeds, and problems can grow from year to year without aggressive effort. Never, ever let it bloom, as I see the plant in the picture doing.

2) You can spray individual dallisgrass plants with glyphosate (Killzall, Roundup, Kleenup and other brands). This will kill the St. Augustine as well, so do your best to focus the application just to the dallisgrass. This will kill individual plants. The lawn will grow back into small dead spots, but if you have to kill an area of these weeds, you should considerer removing the dead weeds and laying sod over the area. This will quickly heal the damage. An area that stays bare of grass for an extended period is an invitation to weeds.

Dan Gill
Consumer Horticulture Specialist

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