by Dr. Sarah Treanor Bois, PhD
Director of Research & Conservation at the Linda Loring Nature Foundation
The idea of “winter landscapes” on Nantucket can sometimes conjure up something dreary. Since we often lack the winter white blanket covering other parts of New England, barren branches and bitter winds can make for a seemingly inhospitable landscape.
Adding a pop of color and some wildlife forage to this landscape is the wonderful winterberry holly.
Winterberry, Ilex verticilata, is a deciduous, native shrub of the edges of bogs and wet places. On Nantucket, it can go underappreciated or undetected throughout most of the year. From Thanksgiving through New Years, however, it is the star of the shrubbery show.
Winterberry is a member of the holly family, but, unlike other members of this family, the winterberry leaves are not pointed or evergreen. The white flowers in June are inconspicuous, and for most of the season you’ll see a dark green shrub with a decent height (generally 6-10 feet).
Once autumn arrives, the story changes. This multi-stemmed shrub is covered with a magnificent display of brightly colored berries (technically drupes) that contrast with the dark leaves. As the season progresses, the foliage colors up to a yellowish color and drops leaving the naked branches to display the red berries in their full glory. That’s when the scarlet berries pop out in a muted late fall/winter landscape. These small, fire engine-red clusters of berries are showstoppers among the surrounding barren twigs and branches.
Around Nantucket, look for the brilliant red berries when driving or walking past marshy areas in particular. These plants naturally occur in forested wetlands as well as along the banks of ponds or other freshwater. As some say, these plants like “their feet wet,” meaning their roots adjacent to water. Winterberry still does well in well-drained soils, so keep it in mind as a landscape plant.
I once heard winterberry called a “living bird feeder,” and I can see why. When the berries first appear (in late summer) they are hard and unpalatable to wildlife, especially among the bountiful buffet offered by other late-summer plants. The berries take a while to soften up, so they are usually passed over by migratory birds passing through in late summer.
That’s why the berries last long into winter—just in time for our resident birds. By the time the berries soften, the birds are ready for their winter feasts. At this point, resident birds have already eaten the other more palatable fruits. Winterberry helps keep them going through the winter. Because of their high visibility in the winter landscape, the winterberry berries are easy for birds to spot. Often you will find several species of birds congregating on a winterberry bush for a feast. In fact, more than forty known species of North American birds rely on these berries as a part of their food source, including American Robins, Gray Catbirds, and Cedar Waxwings.
Deer may eat the berries too, as do squirrels, mice, and rabbits. The plant itself is generally considered deer-resistant, but, like many things, the deer find a way to have a taste. The shrubs can often be found in fountain shapes, as the deer browse the tips of lower branches. The shrubs end up much fuller at the top, where they have grown beyond the deer’s reach.
Winterberry is unique in that the fruits do not drop to the ground after they become ripe, they hang on to the stem and persist for weeks to months. Even under freeze and thaw cycles, the berries hang on. For this reason, they are called “persistent” fruits. Other shrubs with winter-persistent fruits include viburnum, crabapples, bayberry, hawthorns, and sumac.
Winterberry makes a great landscape plant both for the beauty and the wildlife benefit. It’s a win-win-win. First you get attractive greenery during the growing seasons, then a showy flush of berries around the holidays, and, finally, you get to enjoy all the birds that will be attracted to its berries later during the winter season. Planting winterberries is a good way to feed the birds in winter without filling the feeder. Think of all of the songbirds you can attract to the yard.
If considering planting in your own landscape, know that winterberry plants are dioecious, meaning that individual plants may be male or female. Only the female plants produce berries. The male plants supply the pollen to fertilize the female’s flowers so that berries are produced. Unless plants are in bloom or have berries, it is not possible to tell males from females. When in bloom, the female flowers have tiny, green immature berries in the center while the males have fluffy, yellow, pollen-bearing anthers. So, if you plant these in your yard, be sure to have at least a few males to pollinate the female, berry-bearing plants. Those who find little or no berry production may not have a male pollinator plant.
Now that it’s the holiday season, winterberry shines among the dull grays of our island. The red baubles of the berries are like nature’s holiday decorations. That’s what makes them so attractive for tablescapes and other household decor.
If you do decide to decorate with winterberry this season and are planning to clip your own, please follow the general rules of foraging. First of all, make sure you have permission from the landowners. Each island environmental organization has different policies and practices regarding foraging on their properties, so ask before you go. Take only what you will use, leave enough for the remaining population to easily recover—no need to decimate a plant! Do as little damage to the wild plants as possible when foraging. To use a sprig of winterberry, there is no need to kill a whole plant. When done with the decor, discard branches outside where birds and other wildlife can still enjoy what’s left of the berries.
It is important to note that although winterberry is an abundant source of food for wildlife, the berries are poisonous and extremely toxic to humans if consumed.
Enjoy nature’s bounty this season! See you on the trails…