Answer: Ornamental grasses are generally cut back in the spring, just prior to new growth. It won't hurt your plant to cut it back now, but the stubble will remain for several months, until new spring growth begins. Here are some general guidelines for ornamental grasses:
For ornamental grasses to look their best for the new season, the prior season 's dead growth must be cut back. DO NOT cut back flush with the earth! Some grass may be cut back using the lawn more (e.g. phalaris arundinacea 'Picta' or Ribbon Grass), but generally, cut them back by hand or with a line trimmer. I generally leave 4-6 inches of last years grown attached to the plant after cutting back. Some grasses have new growth emerge through last years stems, but eventually the old stems weather away.
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