Text and photos by Leslie Duthie
I often walk in the woods, and being a life-long horticulturist and working almost solely with native plants, I take notice of the trees, shrubs and herbaceous plants that I come across. Some plants elicit a thrill – a less common plant that I see, while others disdain – introduced plants growing in large swaths, hiding or displacing others, and some plants bring me the feeling of calm. For me calm comes from a stand of lush green ferns. Not just any fern, of course. Not the hay scented fern (Sitobolium punctilobulum formerly Dennstaedtia punctilobulum), which can be rampant through the forest floor or on a stone wall. It is pretty, not a favorite, but a commoner, seen in many locations for many reasons. It tends to be thuggish and run over other plants. Nor the New York fern (Amauropelta noveboracensis formerly Parathelypteris noveboracensis), smaller sister of hay-scented fern which also runs and spreads throughout the landscape.
Ferns are ancient plants that colonize the landscape in a variety of ways, mostly by spreading rhizomes that allow them to form patches in the woods. Some spread quite aggressively (like the hay scented or New York ferns) while others take their time. I am often asked ‘But what ecological values do they provide?’ My mental response is these plants, the ferns, have been here for so long – as part of the plant inventory – even if there was no direct connection between ferns and wildlife, they are part of our flora. But I tell people that ferns can be important to wildlife. Birds collect the long lax hairs that cover the young fiddleheads of cinnamon fern (Osmundastrum cinnamomeum). Insects use fern fronds as homes for their young – I have noted this in both cinnamon fern and Christmas fern (Polystichum acrostichoides). Wood fern (Dryopteris) and marsh fern (Thelypteris palustris) provide food for larval lepidoptera. Ferns provide cover for small amphibians, insects and even small birds in the forest. Ferns are part of the ecosystem and provide plenty of ecological value in our gardens.
Back to my woods walk, once I came across a huge patch of evergreen wood fern (Dryopteris intermedia). It was amazing! These ferns stretched as far as I could see, growing in a low, moist area where they had formed a deep, rich patch. I was in awe of the growth of this plant, never having seen evergreen fern like this, with its rich dark green foliage glistening in the dappled light. There were rotting logs, random wildflowers, and sprouting trees among them, but the ferns just covered the area. They had created a huge colony. I found it amazing. I found it calming.
One of my favorite ferns, however, is silvery glade fern (Deparia acrostichoides). Found throughout eastern North America, where it thrives in rich woodlands with moist soil, it likes light, but not direct sun, as many ferns do. It is also tolerant of drier soils and dense shade. I saw it in the wild for the first time not that long ago, near a rocky stream in a rich forest in central Massachusetts. I have grown the fern and it has been fairly easy to get it established in a garden, but I think that is a whole separate story.
Silvery glade fern or silvery spleenwort should be considered a garden worthy species. It is a moderate sized fern, reaching about two feet at maturity. It grows in clumps – all the fronds emerging from a central base, forming a lovely vase-shaped crown of fronds. Its leaflets are split into delicate, rounded lobes providing a nice texture. The real beauty of the fern comes in the tiny, silvery hairs that cover the plant, making it almost shimmer in the light. These hairs give a silvery cast to the plant overall, but it is most noticeable in spring when the hairs are dense as the fiddleheads emerge. Later in summer the sori, or spore cases, on the backs of the leaflets (pinnae) are also covered with a silvery coating known as the indusium. The spore cases are linear and form a herringbone pattern on the back of the fronds. Colonies of silvery glade fern spread slowly, forming lovely patches, or can remain as individuals. They grow with other plants that love rich soils including trillium, rue anemone (Thalictrum thalictroides), wild ginger (Asarum canadense), and asters.
In the garden, silvery glade fern (Deparia acrostichoides) will thrive in average soils and shady nooks in the garden. It tolerates faster draining soils with a little more sand/gravel than it would usually choose, as long as additional water is provided in times of low rainfall or late summer droughts. It grows well and spreads among the hydrangeas (Hydrangea arborescens), black cohosh (Actaea racemosa), maidenhair fern (Adiantum pedatum), creeping phlox (phlox stolonifera), wood aster (Eurybia divaricata), and blue stemmed goldenrod (Solidago caesia) that line the edge of my patio in the shade. Silvery glade fern tolerates enough variety in soils and sun that it is an easy plant to enjoy in garden spaces. The plant looks good throughout the year, holding color later into the fall.
The biggest challenge has been trying to find it in the trade. Be sure to look at online suppliers (preferably one located not far from your area) and ask your favorite nursery to stock it. When we ask for plants, they become more available as retailers look for new things for their customers. Be bold: add a few ferns to your gardens for some unique foliage, color and texture in the landscape, or just a calm place to rest your eyes.
Leslie Duthie is a retired native plant horticulturist. She continues to work in gardens as a volunteer. She has grown hundreds of plants including growing many ferns from spore to maturity in the garden. Leslie is also a member of the Ecological Landscape Alliance board and is the chair of the publications committee. Contact her at Leslie@ecolandscaping.org