Nature Notes

Ferns, Fruit and Fog

Artist and Minnesota Master Naturalist Greg Lecker shares the inspiration he found during a recent trip to the Arboretum.

Visiting the Arboretum: All members and visitors need to make a reservation in advance of their visit to the Minnesota Landscape Arboretum. We hope to see you soon!

By Greg Lecker

A thin layer of fog hugs the ground between Iris Pond and Grace Dayton Wildflower Garden. Morning sun backlights the woodland – and inspires my painted interpretation. 

Morning Glow, painted by Greg Lecker

High humidity on cool mornings with little to no wind – these are the conditions that permit fog to form. Dew also forms in these circumstances – especially when the soil is wet, a condition we’ve not seen much this summer. It may take a few days for the soil to shed this moisture through evaporation.

By the time I’ve hiked to the bog boardwalk on the far side of Green Heron Pond, the sun has burned off traces of fog. I detour from the boardwalk onto the wood chip path laid over a “corrugated” log foundation, I find two different types of ferns: sensitive fern and royal fern on the edges of the bog. Both of these ferns tolerate wet soil and prefer more sun than most ferns that we find in the woodland.

Sensitive fern. Photo by Greg Lecker.

The fronds of sensitive fern are coarse, being divided only once whereas most ferns are divided twice or thrice. The sterile fronds (non-fruiting) are light green and somewhat leathery. Like many other ferns, sensitive fern bears spores separately from the sterile green fronds. The name “sensitive” refers to the plant’s sensitivity to the slightest frost. 

The other fern is much larger; it is royal fern – and, indeed by its size, it reigns over other species ferns.

Royal fern. Photo by Greg Lecker.

Royal ferns are large, imposing ferns, growing erect in a cluster up to four to five feet high! Sterile fronds and fertile fronds differ in appearance. Royal fern is noticeable for the “crown” of fertile growths that stand out from the sterile fronds. These rusty-colored clusters produce the spores that may become new ferns. A mass of large sterile fronds surrounds the fertile fronds and forms the majority of the plant’s mass. Each frond can be considered a “leaf.” Growing outward from the leaf stem (frond rib), leaflets are arranged alternatively. Leaflets resemble those of a pea plant.

After returning to the boardwalk, I find two large shrubs with red berries. They are different plants, distinguished most obviously by the size and arrangement of the red berries.

Winterberry. Photo by Greg Lecker.

The berries of winterberry are clustered close to the plant stems. The berries are scarlet – a tomato-red. Gardeners consider winterberry to be the “Minnesota holly,” because it is hardy in our state and offers intense winter interest. Of special note, the production of berries requires at least one nearby male plant for the pollination necessary for female flowers to set fruit for fruit production. Leaves are simple oblong shapes with pointed tips. Branches and stems are grayish-brown. There is little autumn color associated with winterberry.

Highbush cranberry. Photo by Greg Lecker.

Highbush cranberry (Viburnum trilobum) offers year-long interest:  large clusters of spring flowers and striking autumn color. The species name trilobum describes the three points or lobes of the maple-shaped leaves that turn red in fall. The plant produces prominent clusters of large, bright and shiny red berries atop red stems. Berries are edible after a sharp frost and can be eaten raw and cooked. Berries are high in Vitamin C and taste like cranberries, their namesake. The fruit remains throughout the winter or until harvested by birds. Highbush cranberry is among the many plants that I enjoy on late autumn and winter walks.

 Greg Lecker is a Minnesota Master Naturalist Volunteer.

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