Answer: In late fall after killing frosts have occurred, you may trim off discolored foliage on most perennials. Those that are somewhat evergreen (such as iris and torch lily or kniphofia) may be left as is and then tidied as needed in the spring. The ornamental grasses may be trimmed back in late fall or if you prefer, you may wait until spring. Try to trim them before the daffodils bloom, that way you will be sure to have the job done before they start to grow again for the season. Here is a little more information about what to do.
Enjoy your perennials!
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