Nope! Ornamental grasses respond poorly to mowing and will be slow to regrow if mowed. The Washington Post describes them as “grasses you won’t want to mow.” Some require seasonal trimming, but it’s important not to cut them down too close.  It’s a good idea to bundle stalks of grass with tape and trim them using pruning shears or power hedge trimmers (depending on the size of your ornamental grass). In general, you’ll want to cut about two-thirds of the stalk at the beginning of the growing season to promote new growth.