The Carlisle Mosquito Online

Friday, January 29, 2010


Biodiversity Corner



Last weekend when the ground was still covered with the heavy wet snow that had flattened many plants, a colony of sturdy Sweetfern was protruding through the snow at the Banta-Davis Land beyond the top parking lot. It appeared to be looking around enjoying the warmer temperatures and defying the presence of the snow. I felt some kinship with it.

(Photo by Kay Fairweather)

Name: Sweetfern is so named because its leaves and twigs have a sweet smell when crushed and its foliage is similar to that of some ferns. It is also sometimes called Fern Bush. The plant is not a fern (i.e. it is not a spore producer) but a woody shrub in the bayberry family. Its botanical name is Comptonia peregrina. Even though it is a native of northeastern U.S. and southeastern Canada, it gets its genus name from a British clergyman, Henry Compton, who in addition to being Bishop of Oxford and Bishop of London was also a botanist. When his unwavering support of Protestantism caused the king to relieve him of his duties, he “amply gratified himself with his favorite amusement” of gardening. He was responsible for sending John Bannister, another clergyman, to Virginia in 1678 to document new world plants. The species name, peregrina, is from the Latin for foreigner and also wanderer – as in the English word peregrine. In the case of the Sweetfern it has to be a reference to the way it spreads, or wanders, by suckering. The colony at Banta-Davis may have started as a single plant.

Identification: Sweetfern is an easy plant to learn. It is our only woody plant with fern-like foliage. It can get to be three or four feet tall but much of what I find is about two feet tall. The leaves which are arranged alternately along the stem are long and slender and deeply divided into ten or 20 lobes on either side of the midrib. They die in the fall but some remain attached through the winter. You can still recognize the plant by these dead leaves although they are now brown and many are in a characteristic curl. This time of year you can also see the winter catkins clustered around the twigs near the tips. They will become the male flowers. The female flowers are smaller and they form lower on the twig in the spring.

Habitat: Sweetfern is a common plant in Carlisle. You can probably find it in all our conservation land. It doesn’t grow in the deep shade but can handle partial shade and full sun. It needs an acid soil for good growth. It is able to take nitrogen from the air and can therefore grow in poor soils like on roadsides. It does its nitrogen fixing with the help of fungus-like bacteria called Actinomyces – unlike leguminous plants which use Rhizobium bacteria to perform the same function.

Uses: Native Americans are reputed to have used Sweetfern for a lot of different purposes including incense in some of their ceremonies, a variety of medicinal uses and food seasoning. An infusion prepared from the leaves is supposedly quite palatable and also has a history of being a wash for poison ivy. Deer and rabbits eat Sweetfern leaves as do several species of butterfly larvae. The plants themselves provide cover for small animals and ground-dwelling birds.

Sources: Manual of Woody Landscape Plants by Michael A. Dirr; The Shrub Identification Book by George W. D. Symonds; for Henry Compton history. ∆

Submissions for the Biodiversity Corner are encouraged from everyone. You can write the column or tell me what you saw and I will write it. The only requirements are that it occurs naturally in the wild and was seen in Carlisle. Send a note to

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