Homegrown Habitat, April 2024: Sweetfern
Sweetfern supports 62 species of moths and butterflies as a larval host plant. By Violetcabra – Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=107264091
Sweetfern (Comptonia peregrina) isn’t actually a fern, but a low shrub in the Myricacea family with somewhat fern-like, aromatic foliage. It is native from Quebec south to Georgia and west to Ontario and Minnesota.
This under-appreciated shrub, which grows two to four feet high and four to eight feet wide, has many appealing features: attractive foliage and growth habit, low stature, tolerance of different growing conditions, low maintenance requirements, medicinal and culinary uses, and—last but not least—value to wildlife.
Its rounded, mounding form (one author likens it to a pompom) is generated by attractively arching branches bearing narrow, dark-green leaves that are deeply lobed. When brushed against, the leaves emit a scent that one author likens to Cinnamon Toast Crunch cereal.
(Ernest Hemingway fans might remembers that in his story, “Big Two-Hearted River,” the character Nick Adams picks a sprig of sweetfern and wedges it under his backpack strap so he can smell it while walking through the burned over forest en route to his fishing spot.)
The scent will be stronger when sweetfern is planted in full sun and dry soils. Another benefit of planting in full sun is that the foliage may turn orange and red in fall. Sweetfern’s suckering tendency will result in colonies, where it is especially attractive.
Sweetfern also performs well in part shade. It often grows in sandy or gravelly, well-drained, acidic soils but accepts many different soil types. Sweetfern even grows on sterile soils such as pine barrens and heavily disturbed sites. Its ability to fix nitrogen—meaning it absorbs nitrogen from the air and releases it into the soil—means that sweetfern enriches poor soils. It tolerates drought, wind, and salt but doesn’t transplant easily.
In early spring, dangling, yellow-green male flowers, as well as small, fuschia female flowers, appear on the same branches. The female flowers later develop edible nutlets held in burrs that look spiky but are actually soft.
Sweetfern nutlets are a food source for Northern Flickers, Mourning Doves, and Dedar Waxwings. But this shrub is said to be resistant to deer. Kirtland’s Warbler, a globally rare bird that until 2019 was listed as federally endangered, will often build nests near sweetfern colonies.
As if it didn’t have enough positive attributes, sweetfern supports 62 species of moths and butterflies as a larval host plant, including the gray hairstreak butterfly and sweetfern underwing moth, io moth, and wavy-lined emerald moth.
The developing fruit of sweetfern. Male and female flowers grow on the same branches of this shrub. By Douglas Goldman – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=134055865
Regular readers may be tired of hearing this, but baby lepidoptera, aka caterpillars, provide vitally important food for baby birds–so a plant that attracts insects is a good plant for birds. Locally breeding songbirds need us to grow more such plants in our gardens and public spaces.
Sweetfern leaves can be brewed for tea and used for seasoning. Native Americans are said to have used sweetfern for poultices and to treat fevers. Infusions of the leaves in cold water evidently relieve poison ivy itching, insect bites, and rashes.
This adaptable shrub can be used as ground cover among canopy trees or understory trees and is said to be very attractive when planted around large boulders. It has been highly touted for stabilizing slopes. Due to its tolerance of salt and wind, sweetfern can also be used effectively in roadside or driveway plantings. It would be striking in combination with staghorn sumac in a spacious, sunny bed. Other recommended native companion plants include bush honeysuckle, Virginia rose, bayberry, and little bluestem.
Do you grow this uncommon garden plant? Please share your experiences with us at homegrownhabitat@ctaudubon.org!
—Sarah Middeleer, Landscape Designer, vice chair of the Connecticut Audubon Society.
Resources
Books
Anna Fialkoff, et al., Native Shrubs for Northeast Landscapes, Wild Seed Project, 2023
Mark Richardson and Dan Jaffe, Native Plants for New England Gardens, Globe Pequot, 2018
Jared Rosenbaum, Wild Plant Culture A Guide to Restoring Edible and Medicinal Native Plant Communities, New Society Publishers, 2023
Websites
https://plants.ces.ncsu.edu/plants/comptonia-peregrina/
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c240
https://www.gardenia.net/plant/comptonia-peregrina
https://naturewalk.yale.edu/trees/myricaceae/comptonia-peregrina/sweet-fern-110
https://plantfinder.nativeplanttrust.org/plant/Comptonia-peregrina
https://nativeplantfinder.nwf.org/Plants/827
https://edgeofthewoodsnursery.com/species-spotlight-comptonia-peregrina
