WAMcCormick said: That does not look like crab grass or bermuda grass to me. A clearer picture of it in sharp focus will help a lot toward identification.
Lucy68 said: It may be Bermuda grass. The best time to tell the difference between the two is when it blooms, but it looks suspiciously like Bermuda grass.
The problem is it won't stay small and unassuming and will strangle the Oleander roots. Dig it out. That's the only way I know to get rid of it. Get every little piece as all those stem sections will root and start more plants. I have literally dug up plants to get rid of the Bermuda grass.
purpleinopp said: Looking at the surroundings, I wonder where a grass seed came from? Thinking it was in the soil that came with the shrub.
If it can't spread past the little spot where you're watering the shrub and into the surrounding ground - that looks like concrete, I'm not sure why it's a problem. Where there is nothing growing, why is anything green not welcome - even a hideous vine-grass? I'm not trying to be a smart-alec, I'm genuinely curious. Cardboard or mulch would smother it, or kitchen scraps, if sacrificing anything green in such a spot is desired.
NaturallyGreen said: It's killing my bush. Out of 30 oleanders, this one is the only one that's not thriving, it's turning brown.