Natives to Know: Sweetfern

Sweetfern
Comptonia peregrina

By Joyce Tuharsky WORC Member

Despite its name, Sweetfern is not a fern but rather belongs to the bayberry family: Myricaceae. It gets its name from its leaves which are up to 4 inches long, simple, zig-zagged, pinnatifid, and a lustrous olive green…. looking very much like “fern” fronds. And “sweet” because the leaves give off a sweet fragrance when crushed.

“Pinnatifid”?….That’s a new term for me. I had to look it up: Pinnatifid leaves have lobes with incisions extending half or more to the midrib. Therefore, the leaf lobes are not discrete leaflets, but remain connected to each other.

Sweetfern is native to the eastern US and Canada, often found in open woodlands, lakeshores, and along roadsides or other disturbed areas. It is a low-growing (3–5 ft high), thicket-forming shrub with a round form.

This plant bears separate male and female flowers in catkins that can bloom from May through August. The male catkins are elongated and copper brown in color; the female catkins are shortened yellow-green ovals. Though inconspicuous, the flowers are loved by hummingbirds and pollinators, especially since the blooming season is long. Burr-like fruits containing nutlets develop from the pollinated female catkins.

Sweetfern is a larval host to the Grey Hairstreak butterfly (Strymon melinus), as well as a variety of moths, and provides valuable cover for small birds and wildlife. It is deer resistant and can withstand strong winds, periods of drought or flooding, road salt, and very cold temperatures. These attributes, along with its solid root system, make Sweetfern an excellent choice for soil erosion control on steep banks or slopes.

A compelling attribute of Sweetfern is its ability to partner with a special bacterium to convert atmospheric nitrogen into a form that plants can use. This enables Sweetfern to thrive in poor soils and tolerate conditions other plants cannot. The nitrogen converted by nodules along the roots is passed along to other plants underground. The soil is also enriched as Sweetfern’s fallen leaves decompose.

In the garden, Sweetfern’s lacey, lush foliage contrasts nicely with broad-leaved plants. It makes a hardy ground cover and is a great choice for mass plantings or naturalizing sites where other plants perform poorly. On the other hand, it may not compete well with more vigorous plants in fertile soils. In autumn, the leaves turn an interesting mixture of yellow, orange, and burgundy. The leaves can be used to make tea. Also, some claim that tossing the leaves on a campfire will keep mosquitoes at bay.

Sweetfern prefers full sun to light shade, and well-drained, slightly acidic, sandy to loam soil—but not clay. Propagate by root cuttings; seed germination is difficult. Once established, Sweetferns is low maintenance, requiring little supplemental water or pruning.