The Carlisle Mosquito Online

Friday, January 13, 2006


Biodiversity Corner Winterberry

American Robin on winterberry shrub. (Photo by Tom Brownrigg)
Name: Winterberry is Ilex verticillata, a member of the holly family and a native of northeast America. It also goes by the names Black Alder, coralberry, and fever bush. Every now and then I remark about issues with common names. "Winterberry" is fine but I have trouble with "Black Alder." The problem is that there are real Alders — in the genus Alnus. They are members of the birch family and quite distinct from the hollies. In a convoluted plot of confused identity worthy of Shakespeare, Oscar Wilde, or the Black Adder writers, you find that the European Alder (Alnus glutinosa) also goes by the common name Black Alder. It's enough to addle one's brain.

When and where seen: Winterberry is easy to spot this time of year because the bright red berries are not hidden by the leaves and the birds haven't yet taken all the berries. You can see a small grouping of winterberry plants as you drive towards Chelmsford on Lowell Street. They are on the right hand side of the road just before the turnoff to the transfer station. You can also see some in the back of the Post Office and at various places in Great Brook Farm State Park.

Identification: Winterberry is most easily recognized in winter by the round red berries which are clustered closely to the twigs. It is a multi-stemmed deciduous shrub that likes to grow in acid soil along streams or in other damp places. Typically, it gets to be about 6 to 10 feet tall. It has small white flowers in the early summer. The leaves are elliptical and have a serrated edge — they are not at all like the traditional Christmas holly leaves.

Food and drug department: The berries are poisonous to humans but provide food for wildlife, especially robins, bluebirds, and waxwings. I found the following reference, dated 1905, to birds feeding on winterberry in Ontario. "The birds avail themselves of the berries when better fare is denied them by the snow, and it is credited with giving its peculiarly unpleasant flavor to the flesh of grouse in December." Winterberry bark was used by native Americans to provide a variety of treatments including relieving fever, hence the common name fever bush.

Landscaping: Winterberry is listed by the Cornell Lab of Ornithology as one of the five important species of shrubs for the bird-friendly landscape. (The other four are northern bayberry, staghorn sumac, some viburnums, some dogwoods, and winterberry.) Winterberry is dioecious, meaning that male and female flowers are borne on separate plants so you will want mostly female plants. There are many cultivars to choose from. They don't need to grow by streams or swamps, but since they like their feet wet, they are a good choice for poorly drained areas. The best fruit production occurs on plants in full sun.

New Year resolutions: Since the first topic for the new year is the winterberry, what better source than Wendell Berry from whom to draw inspiration for new year resolutions? Try these: "Ask the questions that have no answers. Invest in the millennium. Plant sequoias." If you are not ready for sequoias, get your feet wet with Winterberry.

References: University of Connecticut plant database at (search for winterberry); and search on "bird-friendly shrubs".

Mystery bird sighting

There is an unusual bird visiting feeders on Baldwin Road. It has been spotted by Susan Emmons and Janet Hentschel. At first glance it appears to be an aberrant form of goldfinch. It is of goldfinch size but has a lemon-yellow head and bright pinkish-red feet and a pink bill. Ken Harte thinks it might be a Sudan Golden Sparrow, an escaped cage bird. Have you lost a pet bird?

Photos of this bird can be found at:

Submissions for the Biodiversity Corner are encouraged from everyone. The only requirements are that it exists in the wild and was seen in Carlisle. Send a photo and some field notes to Kay Fairweather at 392 School Street, Carlisle MA 01741 or to

2006 The Carlisle Mosquito