I've used Flink's Instant Meadows.  Works as advertised.  They're fairly resource efficient, given how mesh plants eat up polygons.  Flink arranged the grass blades so that a patch does not show obvious square edges, so you can just scatter a few patches here and there.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5