Greenery in the Winter Woods

On this Winter Solstice, the forests are now colored in various shades of tan and brown here in southern Connecticut. But here and there are patches of green. Whether they signify rebirth, a new life, immortality, or peace, plants that are still green have played an important role in almost every holiday celebration, particularly during the winter.

Plants that remain green in winter can still photosynthesize using the sun’s light plus water to produce sugars to “feed” themselves.

How are these plants able to stay green and keep from freezing? Cold stress is just as lethal to plants as heat stress. When water inside the cells freezes, it expands, causing the cell membranes to burst and the cells (and plant) to die.

Many plants in winter respond to colder temperatures by accumulating sugars and moving them to the leaves. Those sugars lower the temperature at which ice forms—like putting salt on the roads.

Another adaptation plants have evolved for protection in winter is to make proteins. This helps to stabilize cell membranes and keeps them from bursting.

We’ve had several nights below freezing and yet the Pansies (Viola spp.) in my window box are still green and in flower! I think, though, it is just a matter of time before freezes will kill the Pansies, so I’ll soon be moving them to the porch.

Despite snow and a number of freezing nights, the Pansies (Viola spp.) in my window box have remained green and in flower. Photo by the author.

Look for evergreen ferns on your next winter hike. I say evergreen, but no plant is truly evergreen. Plant leaves and fronds eventually die and are replaced. Marginal Wood Fern (Dryopteris marginalis) and Christmas Fern (Polystichum acrosticoides) are two ferns that are easy to find now and throughout the winter. They are often seen growing near one another.

Two species of “evergreen” ferns, light green Marginal Wood Fern and deep green Christmas Fern, found growing along the Farmington Canal in Hamden, CT. Photo by the author.

Marginal Wood Fern is a light blue-green with broad, twice-compound leaf blades (divided into leaflets that are further divided into more leaflets). The Christmas Fern is named because its dark, leathery leaves are green at holiday time, and because each of its leaflets are lobed like a Christmas stocking.

Marginal Wood Fern is named after the sori, or spore packets found underneath and along the margins of the pinnules. Wasp32, CC BY 4.0, via Wikimedia Commons.

Patches of these ferns provide winter cover near the ground for songbirds. Some bird species use parts of the fern’s scale-like hairs to build nests come spring.

Christmas Fern is named for the lobes on the pinnae (leaflets) that look like a Christmas stocking. Photo by David J. Stang, CC BY-SA 4.0, via Wikimedia Commons.

Both of these plants feel rather waxy to the touch—yet another great adaptation for protecting leaves in the cold. Many coniferous, or cone-bearing, trees have waxy leaves or needles too. Coniferous trees and native, broad-leaved evergreens such as Mountain Laurel (Kalmia latifolia) and Inkberry Holly (Ilex glabra) are very important for birds and other wildlife in the winter. These plants provide shelter from harsh winter winds and protection from precipitation.

If you see what looks like miniature pine trees growing in a line on the forest floor in winter, you’ve found one of the clubmoss species, an ancient line of fern relatives in the genus Lycopodium, Dendrolycopodium, Diphastiastrum, or Huperzia. Nicknamed ground pine or running pine, and only a few inches off the ground, the ancestors of these plants during the Jurassic Period were more than 100 feet (30.5 meters) tall! Please don’t cut club mosses for holiday wreaths. The plants grow very slowly and local patches can be wiped out by collecting.

Ground Pine or Running Pine (Lycopodium clavatum) is actually a small, spore-producing fern relative. Sesamehoneytart, CC BY-SA 4.0, via Wikimedia Commons.

Even though I know we’re in for more frigid temperatures, I look forward to the increasing light of longer days from here on. The winter’s greenery invites you to look forward to spring.

Wishing you peace and a healthy, prosperous New Year.

Published by Jim Sirch

Jim Sirch is the author of Beyond Your Back Door, a weekly blog about nature in your neighborhood. He is also Education Coordinator for the Yale Peabody Museum, a UConn Master Gardener and board member of his local land trust. As a trained naturalist, he brings a deep understanding of geology, plants and wildlife and how they interact within a particular ecosystem. He holds a B.S in Forestry from West Virginia University, a B.S. from Miami University in Science Education; and an M.S. in Environmental Studies Administration from Antioch University. He is also the 2014 Sigmund Abeles Award recipient from the Connecticut Science Teachers and Supervisors Association for outstanding science teaching and professional development.

21 thoughts on “Greenery in the Winter Woods

  1. Merry Christmas Jim! This was an interesting article. I still have some lettuce greens hanging on in my window box off the kitchen. Love that they want to survive the cold temps we’ve been having. Looking forward to our native seed starting workshop in person this year at Hadlyme Hall 1/21/23. See you then Happy New Year too! Diana (Fiske)



  2. Thanks Jim!
    These wonderful posts make me feel like I’m taking a walk in the woods with you.
    Glad also to be reminded of the Go Bonany resource.
    Happy Holidays to you and yours


  3. Luckily as you mentioned some ferns are still green as are mosses. But as you know pansies are not native, and many of the green plants that I see are not only foreign but Invasive such as garlic mustard and other really nasty looking things that have shown up in recent years.


    1. Hi Susanne, the large pansies in my flower box are not hardy through the entire winter and not invasive. But you are totally right about invasives such as garlic mustard. Garlic mustard is a biennial, spending the first year as green, basal rosettes through the winter and flowers the second year and dies. I am thinking of string trimming those leaves soon. Best not to dig it up as you will disturb the seed bank and bring up more seeds, but just cut flower stalks.


  4. Such a nice topic for right now. I enjoyed learning about the ferns and I’d never heard of club moss before. So very interesting.


  5. Reading your essay is as relaxing as a walk in the woods! Wishing you all good health and happiness, and lots of nature walks, in the new year.


  6. I just caught up on posts that I had “flagged” and also reread others Thank you. You brightened up another dreary day. I wish you peace & health in this new year.


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