I would think that anything that would burn the grass would burn the rose too. I removed a lawn in order to plant my rose bed, so I occasionally get grass "weeds". I just pull the little tufts of grass out. I heavily mulch, which cuts down on the weeds.

I used Grass B Gon about 3 days ago, the grass is still there.

I am afraid I find it necessary at times to use Roundup on the Kikuyu grass that has become a feral weed in my area. Even when you plant a nice turf lawn it sooner or later has kikuyu runners appearing. If I tried digging it out I'd be half way to China by now, the runners travel so deep! When it appears in my rosebeds I paint the RU on with a paint brush so at least there is no spray drift to affect the roses or other nearby plants. I believe there are other sprays but they are not available to home gardeners in Australia.

I think your idea is good, Zack, but I don't think it's in the pipeline. With all the new regulations on herbicides and usage I doubt anyone's looking into that.

I find that I can kill grass in two or three days with high nitrogen liquid fertilizer.
It might developed into a useful tool for advanced rosarians who don't want Roundup anywhere near their roses. As I've mentioned elsewhere, I just move the grass to fill holes in the lawn. I guess that means I don't grow too many roses :-}.

Zack, would you please let me know the 3 numbers on the high nitogen fertilzer and the name of the brand? I want to try it. It's much easier than pulling. :-)

Thank you very much Zack. Do you mean to mix the fetilizer with water before apply to the grass? Or wet the grass first, then apply the fetilizer on the grass? Please advise. Thanks

Zack, I got a 15lb bag today. Tried on a small spot before dark, and sprayed some water on it with a spray bottle. Hope I did it right. If I mix the scotts 32-0-4 with water, how much water/lb? The Grass Be Gone only worked half way, the grass is not totally gone yet, it has been a week already.

Reapply the Grass Be Gone. Why give up?

Or use a glyphosate. But same deal, can take multiple applications.

Ammonium fertilizers are often used in tandem (as adjuvants) with herbicides to enhance their action. Ammonium sulfate (21-0-0-24S) is commonly used.

It can take more than one application of Grass-be-gone to get rid of the grass completely.

Thanks for everyone's input, may be it's easier just spray Grass Be Gone a couple more times. :-)