The lone voice of horticultural reason
Don’t cut ornamental grasses down at season’s end.
If you prefer to cut your perennials down at the end of the season, as many gardeners do, spare your grasses. Short, mid-sized, or tall, most ornamental grasses overwinter better if left alone in the fall. It may relate to their ancient genealogy, the fact that for centuries they have stood tall in winter dormancy, then burned off in spring by natural prairie fires, or maybe I just made that up.
No matter. My experience and that of others points clearly to the fact that grasses show more vigor in spring if left alone for winter, then cut to the ground about the time you notice buds on trees and shrubs in your yard beginning to swell.
Some short, tufted grasses, particularly Festuca cinerea ‘Elijah Blue’ and the shorter varieties of Carex don’t like being cut back at all. If a grass you grow reaches less than twelve inches at maturity, leave it alone in spring and see if last year’s growth doesn’t simply dissipate as fresh spring growth rises.
The Renegade Gardener