Answer: I would protect them with mulch. A foot or more of loose organic material such as straw can be used. Don't use hay as it often contains weed seeds. And don't use such light, airy mulch if you have rodents, as this will only provide them with a home with your perennials as their winter food supply. It's better to surround your plants with pine boughs if rodents are a problem. Apply mulches late, around late November, as perennials need some cold to harden properly. Remove mulches as early as possible or when snow melts. In the North, this should be done at least by April 1 and during a period of several warm days. Leaving mulch on too long will lead to tender and weak growth as perennials grow under the mulch.
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