1. Try to clear your cache before starting the game. If that does not work, just reinstall the game. 2. Was it necessary to make a SECOND thread to share this problem?
This glitch is caused by the newest AMD drivers. Revert your graphics card drivers to the previous version or disable grass.
^ This Some users also reported that using the Latest Optional AMD Driver should solve the issue too (you must press 'Clear the Cache' button before launching the game on the new drivers)