With the PC version, if you have the second patch installed ( DKS / FoV ) I believe that should be in the graphics options somewhere. The ability to disable the loading of vegetation was added in an earlier hotfix.
i did not see anything under options to turn grass completely off just set it to low/med/high However i did some dig through the D2 folder and found what I was looking for. For anyone else who would like to turn off grass its in ..
Divinity II - DKS\data\globalswitches.xml
<!-- LoadVegetation: Set to 1 to load all vegetation. --> <!-- Set to 0 to not load any grass or other vegetation (may increase framerate on low-spec pc's). --> <!-- DEFAULT = 1
the actual value to change appears at the end of the globalswitches.xml LoadVegetation="0"
On my Xbox it is all nice place with all the beautiful vegetation
Note : Rolling in the grass is another way to make the grass flat so the grass can't no longer anoying you all the time (just kidding!)
On 7th of february 2015 : I start a new adventure in the Divinity world of Original Sin, it's a Fantastic Freaking Fabulous Funny ... it's my All Time Favorite One !