I'm not expert in the plant department but... It just looks like they are using low quality alpha channel for the current grass/plants (Black/white for transparent on/off, no grey scale in between for blending) on top of that it it looks like low rez alpha hence the stair stepping effect. There could be overdraw or light issues with having it blend better but again I'm no expert in this part of development.

I agree though it could use some love, the chisel alpha thing always creates a flicker/sparkling effect over the scene while running through that always drives me batty.