Many gardeners like to “clean up” their gardens in the fall (read Are You an Excessive Gardener or a Laid-back One?), but pretty much everyone agrees that ornamental grasses should be an exception to that rule. While most turn different shades of beige and brown as the season advances, they still remain attractive. Their feathery flower heads generally turn an attractive silver color and remain on the plant over the winter. Against a background of snow, they are very attractive indeed.
Even grasses grown as annuals, like purple fountain grass (Pennisetum x advena ‘Rubrum’), which is subtropical (hardy only to zones 9 and above), looks perfectly charming when leaves and feathery flowers have turned beige and can certainly be left standing all winter.
Plus the seeds of ornmental grasses are a major food supply for birds… and you wouldn’t want to be accused of starving our fine feathered friends, would you?
When spring comes around, just cut grasses back to the ground and the perennial ones will soon start to sprout anew.