I live in the desert and wondering what kind of weed this was? and how to easily remove them. The big rocks just make these weeds harder to get rid of.
a closer pic
Not sure what grass it is, although has some resemblance to downy brome, but it could be a form of blue grass. In any case, it looks like an annual. Probably germinates in the late fall, then takes off early in the spring and sets seed, maturing and dying by summer. As an annual, it reproduces by seed, so preventing seed will cause it to decrease in quantity from year to year as you work the seed supply out of the soil.
If the bed it is growing in is all rocks, you could work/move everything around in the fall (till without tilling the rocks under) to kill the seedlings while they are small and easy to kill, or cover with cardboard or black plastic to starve them of light. Additionally, glyphosate or the common grass killers found in the garden section of your favorite store should take care of the grass, but it will be easiest to kill using whatever method you want in the fall. In the spring when it starts putting out seed heads it will be less susceptible to herbicides and harder/more time consuming to kill with other methods.
Doing some research online I think it's a type of foxtail weed. I've heard also heard that the burrs at the top are a problem for dogs. I think all I can do to kill them is a weed killer spray.
I don't know what it is but it is definitely a grass so you would need to get a grass killer. Broad leaf weedkillers won't hurt it.