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Some Northland ferns thrive in winter

A group of rock-cap ferns cling to the side of a cliff on a winter day. Note the brown sori under the leaves. (Photo by Larry Weber)

Maybe it’s because of the winter holidays. Maybe it’s because the deciduous plants that surround us are devoid of leaves and looking a bit bland in their gray, cold winter attire. Or maybe it’s just because we seek some variety.

Whatever the cause, we seem to notice the green plants with us now in winter more than other times. During summer when greens dominate the scene, we’re not likely to single out ones that have this color. But at this time we see them better.

When driving or walking in the region now, we see the conifers in their heights and numbers and realize that conifers may be a lot more diverse and abundant in the Northland than we think they are during the rest of the year. In many yards, parks and roadsides, various imported conifers have been planted and are quite noticeable, but 10 kinds of native conifers can be found here, too.

Best known, and maybe the largest, are the red pines and white pines. Both are well-loved and when in a protected site, can grow to be a couple hundred years old and maybe 100 feet tall.

Our third native pine, the jack pine, is here, too, but not as large. Among the spruces, white and black, white is more likely on hillsides while black is in marshes, bogs and swamps. Their shape is more pointed than that of the pine trees. Balsam fir (usually called just balsam), also pointed, joins the spruces to make us think of the “Christmas-tree shape.” White cedar and junipers are thicker and grow more rounded, as can be seen in yard shrubs. The small yew, usually more of a bush, is smallest of all. And the tamarack, the only conifer to drop all of its needles at once, is also a local resident conifer. (In northern Wisconsin and to the east, grows another large conifer, the hemlock, but it seems to avoid Minnesota with only a scattered small population here.) With a little practice, it is possible and even likely that we can recognize these different evergreens while we pass by. They truly stand out in our winters.

Getting deeper into the woods, we can find a few other evergreen plants. The miniature mosses cover the lower parts of many forest trees, but also logs, rocks and even some soil. In their abundance, these lowly plants stay green all winter, usually under snow. Nearby, other plants, clubmosses (not related to mosses), also called princess pines, ground cedars or Lycopodiums, spread out on the forest floor. Being only 6-8 inches tall, they are likely to be overlooked all summer. Once the leaves drop, during AutWin, they show up but normally get blanketed by snow for months.

Despite the name, clubmosses are not mosses but instead are related to the ferns. Ferns grow tall, often 4-6 feet, in the Northland forests during the summer. With the coming of chilly times they drop back to the ground, remaining alive underground in spreading rhizomes. There always seems to be exceptions in nature and during a couple of recent walks, I found two kinds of ferns that were still green.

Most common, the wood fern, thrives in these forests. Being smaller than many other ferns, it can get overlooked until autumn. When others turn brown and drop, the wood fern remains green. It, however, is not a true evergreen and after a few winter months, the wood fern will also fade.

The other fern that I noticed is a true evergreen. Rock-cap fern gets its name from where it grows, on cliffs or on large rocky sites. Clinging to life in such precarious locations may seem tough, but the fern does very well here and is able to retain its green leaves all winter. Rocky and vertical sites, as where this fern grows, are often windswept with not much snow cover. I have seen the rock-cap fern exposed to the winter weather in the midseason.

Such places can also be quite arid. The ferns and any other plants growing here run the risk of dehydration. With the moisture that we have had in this mild month, that was not happening with the ferns that I found. In previous years I’ve noted some that responded to the dryness by curling up to prevent more water loss. Warming and thawing along with more precipitation allows the ferns to grow as normal.

It is a long way to next spring, but on the undersides of the fern’s green leaves; in ferns, leaves are called fronds. I saw the presence of many sori (pronounced like “sore eye”). Here the reproductive spores are formed and stored.

These tiny seedlike structures will spread out in the milder wetter days of next spring to begin to grow new ferns. But for now in winter, it’s great to see some evergreen ferns, along with other evergreens, in the Northland woods.

Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o budgeteer@duluthbudgeteer.com.

Larry Weber

Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods,” “Webwood” and “In a Patch of Goldenrods.” Contact him c/o budgeteer@duluthbudgeteer.com.

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