This is Eragrostis curvula, weeping love grass. Not the same as Mexican feather grass which tends to crown rot easily here, or Mexican heather. We found the Spanish dagger like this in a specialty nursery in Fort Worth. They are straight when small, but as the heads get bigger they make weird bends (and eventually fall over, and shoot up new ones.) You have to have a tolerance for change with these guys!

Weeping love grass