Oh, we're mental, alright!
Here's a clip about pruning ornamental grass:
Here, here, and here talk about pruning ornamental grass.
I'm not really sure the type we have in our yard. Not sure if it is pampas, or what.
Before in our yard, you can see a lot of dead fronds. I wanted to get rid of those so that new growth could push through:
Pretty much, you just cut it back with whatever you have. My father-in-law used a weed-whacker, then went back over it with some hedge trimmers.
After in our yard: