One potential issue with this is that gers actually leave circular patterns once they've been removed, where the soil is disturbed and the grass is light-starve

One potential issue with this is that gers actually leave circular patterns once they've been removed, where the soil is disturbed and the grass is light-starved or dead. It takes a couple years for those to fully disappear after the ger is removed. Gers themselves can be any color. White is traditional (from a time when white wool was more expensive), but not mandatory.