Cold Protection for Your Garden Plants

Here comes another cold snap for the Puget Sound! And here are some quick tips for protecting your less-hardy plants from cold damage. Especially a good idea when temperatures dip into the 20s for several days.

 

Check Local Temps

Look for predicted temperatures in your neighborhood, not just the regional airport. Your location could be 10º different from a spot half a mile away, the difference between the top of a hill and the bottom. But always assume colder — better safe than sorry.

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Know which plants to protect

If you’re not familiar with a plant from its history in your garden, look up the hardiness rating (the coldest temperature it can typically survive). Plants with a hardiness rating of 10ºF (USDA Zone 8a) or lower are rarely at risk in the Puget Sound region. Plants for Zone 8b, 9 or warmer might need protection when we freeze. Of course, if it’s unclear you can always ask us!

 
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Water before the freeze

If a hard freeze is forecast a few days in advance, and if it hasn’t been raining much, water your plants before the freeze. A streak of sunny, dry, cold days with a daily freeze/thaw cycle can hinder plants’ water uptake, causing dehydration and more winter damage. 

 

Insulate

Cover or wrap vulnerable plants with burlap, old blankets or towels, straw or something else to create insulating air around the plant, such as Harvest Guard’s Plant Protection Bag (top right). Remember to tie or weight down your cover material. Also, you can mulch over roots of perennials or shrubs that might be affected, with compost, leaves or conifer boughs. Note that a layer of snow actually helps insulate plants! Dry cold is the bigger threat.

 
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Move or protect containers

Especially hanging pots. Huddle them against a building or under an evergreen tree, or otherwise insulate them (as discussed above).

 
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Brush off heavy snow

If our infamous wet, heavy snow does show up, watch for fragile branches on trees and shrubs, and brush them off where possible, to minimize breakage. Any snow covering low plants is fine — it insulates, as mentioned above. But if they have extremely fragile branches, best to cover them with something that resists the snow’s weight.

 

Here are links to more detailed articles on winter protection in the Northwest:

“Getting Ahead of Winter” - The Garden Hotline

“8 Tips to Gear up Garden for Cold Weather” - Oregon State University Extension

Not sure which plants are more vulnerable to cold? Or other questions? Don’t look so glum… Visit us, comment here, or reach out to us anytime at garden@swansonsnursery.com. We’re here to help!

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Post updated November 2022