Fiber Optic Grass is a neutral grass. Where temperatures get colder than 20 degrees F, the plants should be treated as annuals. Once the grass turns brown it can either be removed immediately or removed in the spring. It should not be expected to live through the winter and begin growing again in the spring.
 
In areas where winter temperatures remain above 20 degrees it should be considered a perennial and the following information should be useful. Evergreen or neutral grasses are usually plants that look like grasses but aren't actually classified as grasses, they are generally called grass-like plants.
Divide evergreen or neutral grasses and grass-like plants in spring only.
Evergreen grasses don't ever go dormant. Dividing plants wounds them to some degree. For evergreen grasses this wounding will really affect their ability to live through the winter.