Looks like the same thing that's springing up in my neighborhood, up to a foot tall or more. Looking at weed pics, it's hard to tell if it's poa annua, aka annual bluegrass, or annual rye. Not sure it makes much difference, as far as controlling it. Roundup kills mine, but also kills the St. Augustine. The most effective remedy may be a fall pre-emergent. You might post this on the Weed and Lawn Care forums. Don't let those seeds mature.

Kinda hard to see, but may be annual bluegrass. If so, it will disappear come warm weather.

Looks like a grass, definitely. Use Grass-B-Gone -- works wonderfully on grasses ! and doesn't usually bother nearby perennials.

Thanks all! It looks like bluegrass indeed.

These are all mixed in with my standard Bermuda lawn...not in a flower/plant bed.

I don't want to kill the Bermuda.

-Chris

Here is a link that might be useful: bluegrass pic

Kinda looks like the only effective agents, for this time of year, aren't available to the home gardener.

@whitecap

like Atrazine or Celsius?

I finally got rid of it by pulling up every sprig early in the year. Now there is just an occasionally plant from seeds that the wind blows in from the neighbors.

As an experiement I tried Grass-B-Gone by very carefully dripping it ONLY on the foliage. It killed it, but it also killed a little circle of St. Augustine grass around it. Seems it goes into the roots and transfers to the roots of other grasses around it. Grass-B-Gone does not harm broad leaf plants.

Since it is an annual it will die back with hot weather, but it has shaded desirable grasses and somewhat impeded their growth by then. The best solution is digging it AND applying pre-emergent weed killer at the recommended times next year. Not positive, but I think that would be in Feb..

Chris, it's been a while since I "boned up" on this, and I've about exhausted my little store of memory, but check the discussion at Annual Bluegrass Management Guidelines UC IPM. They list half a dozen "postemergents" safe for use on turf, none of them available to us Do-it-yourselfers. (I can't post links.)

I think it's fine to use round up this time of year since the bermuda hasn't really taken off (here at least). That burmuda will fill in very quickly. And the advice to use a pre-emergent to prevent it next winter is very good advice.