I was trimming a wax myrtle the other day when I caught a whiff of its sweet fragrance. It reminded me of my many treks through the Maine wild landscape. Walking through waist-high patches of sweetfern gave my clothes an aroma that lasted all day.
Sweetfern (Comptonia peregrina) is not actually a fern at all. It’s a flowering plant in the same family as wax myrtle, sweet gale and bayberry. Similarly, it can be used as a spice, too. This shrub has an even stronger taste and aroma than any of those. It also has the same insect repelling properties.
According to some sources, it can be found in our area, but I’ve never encountered it. I have seen it in a few open places in the mountains of western North Carolina though. However, it’s not a major species there either.
It’s a common staple to sunny waste places in northern regions of the US and is hardy as far north as central Canada. It also has a unique quality which enables it to thrive on infertile soils.
Like legumes, sweetfern can derive nitrogen directly from the atmosphere through bacteria that live on its roots. The bacteria can split nitrogen molecules and combine them with hydrogen to form ammonium compounds plants can use. In exchange for the nitrogen fertilizer, sweetfern roots provide sugar to the bacteria.
This relationship makes sweetfern a great conservation species. It quickly colonizes disturbed sites and thrives in full sun. Plants also form mats of underground stems that help keep soil from eroding. Sweetfern tolerates drought well, and this further enhances its conservation qualities.
While sweetfern is a flowering plant, the flowers are not showy. Separate male and female flowers are found on the same plant, and the tiny nutlets that form are edible and very palatable. I’d consider them survival food though. They’re good, but it would take considerable effort to procure enough to save for future use.
The fern-like foliage is the attractive feature for this species. Plants make a great naturalizing border in their native range. Here in eastern North Carolina we are probably a little too far south for this wax myrtle cousin to adapt. Plants are also deciduous, and many folks prefer most of their landscaping to be evergreen.
Foragers traveling to northern states or eastern Canadian provinces might wish to collect some foliage from this shrub. It makes a tasty tea and simmering potpourri. Herbalists prize sweetfern for medicinal use.
Wildlife utilize sweetfern for food and cover. Small birds and mammals make homes in its thick undergrowth. Several butterflies rely on its foliage to complete their life cycles. Deer and rabbits use sweetfern for winter browse. It’s not their favorite food, but it provides sustenance when food supplies are limited.
Sweetfern is the alternate host of the sweetfern blister rust disease caused by the fungus Cronartium comptoniae. This affects pine trees with needles in groups of two and three. This includes many of our native pines. White pine isn’t susceptible. Economic losses for the trees are small, even in sweetfern’s native range, but the disease could be a consideration for some wishing to establish sweetfern here.
Ted Manzer teaches agriculture at Northeastern High School.