Protecting Perennials For The Winter

Once a heavy frost begins to cover the perennial gardens we hear this question from Cape Cod residents: “How do I need to protect my perennials over the winter?” The answer to this query largely depends on the perennials that you’re growing. Most perennials that are hardy on the Cape where we’re in a warm zone 6 to a cold zone 7 usually don’t need protection at all.  If you’re growing plants that are hardy in a warm zone 7 you’ll probably want to apply something that can help them survive the winter. Here are some details:

1. If the winter is mild the ground may not freeze much and so perennial plants come through in good shape. If it’s a cold winter the best protection for perennials is a good snow cover.

2. Marginally hardy perennials are best protected in late-December or early January. Hay or salt-marsh hay is good protection as are pine boughs. Don’t use whole leaves as they will mat down over the winter and become a wet, heavy layer that can smother perennial plants. Plants that are listed as hardy in zone 7 could use protection. Use pine boughs for plants such as lavender, verbenas, or rosemary because these will keep the air circulating so they don’t rot. Winter moisture that is held around the plants is worse than not protecting them at all.

3. In a mild winter take any protection off in March. In a cold winter wait until the end of that month.

4. Sudden shifts in temperatures are worse for all plants than if the winter slowly gets cold and stays cold…be aware that if it’s warm early in the season and then suddenly the temperature drops into single digits you’re likely to lose more plants due to winter kill. Mulch won’t help very much when sudden extremes are the issue.

If you have any questions about your specific perennial plants on Cape Cod, be sure to stop into our store or give us a call.