Vanishing Winter Berries

For a brief time in early autumn, the combination of bright red fruits and dark green leaves gives winterberry holly the look of the traditional Christmas holly.

In early October of this year, every branch on the two winterberry hollies in Marjorie’s Garden, both the cultivar ‘Winter Red’, was packed with red berries.  By early November, yellowed leaves covered the ground around each shrub and I looked forward to standing at the window near the wood stove in December, watching snow fall through naked gray branches covered with bright red fruits.  But it was not to be.  I looked out on the garden one day this past week and the berries on both shrubs had vanished.

My first thought was that the berries had abscised for some reason, so I went out to check.   There were no berries on the ground around either of the two plants.

Ornithologists tell us that the fruits of winterberry (Ilex verticillata) are relatively low in fat content and thus birds take them only as a last resort during midwinter thaws when the higher energy fruits are gone.  Still, catbirds ranked high as likely suspects, specifically the catbirds that we watched devour the ripe serviceberries in June and that we suspect ate many of the grapes as they ripened in late summer.  But then I realized that our well-fed catbirds had probably left the garden for points south long before the holly fruits disappeared.

In addition to catbirds, there are more than 48 bird species reported to eat winterberries, including bluebirds, brown thrashers, cedar waxwings, flickers, mockingbirds, robins, chickadees, and the various game birds.  All of these birds are day feeders and I could hardly have missed them feasting on garden shrubs in broad daylight.

Other possible suspects include red squirrels and chipmunks, both abundant in our garden.  And what about the foxes that visit the garden?  They usually come at night, although we once spotted one sunning on the trunk of a fallen spruce at the edge of the garden.  I did find “foxes” on a list of wildlife known to eat winterberries.

I had not thought to add crows to the list of possible suspects until Elizabeth Curran, good friend, gardener, and keen observer of the wild, mentioned that she often sees crows devouring the winterberries in her neck of the woods.  Marjorie’s Garden has a resident population of crows.  In spring they sit on the highest branches of an old spruce snag, taking note of where we sow peas so they can pluck out the germinating seedlings when they break through the soil.  In late autumn they swoop down from the same branches to scavenge oat seeds sown for cover crop.  Their presence certainly increases the uncertainty of garden success and I would not be surprised to learn that they took the winterberries, more for sport than sustenance.

To anyone living within the native range of winterberry holly, from New Brunswick to the Gulf States and west to Minnesota in the north and Louisiana in the south, it is a familiar plant, at least in winter when its short-stemmed red berries sparkle in the sunlight from roadside wetlands.  Its habitat includes the drainage ditches that run close to the highway and this is where people will stop in early winter to prune berry-laden branches for holiday decorations.

Both winterberry and another deciduous holly, the catberry (I. mucronata, formerly Nemopanthus mucronatus), form impenetrable colonies in swamps and bogs throughout New England.  The two species are easily distinguished in fruit, the thread-like stalks of catberries much longer than those of winterberries.  In late winter, however, after both leaves and fruits are gone, I have a difficult time telling them apart.

In the wild, I. verticillata can reach 10 feet or more in height with a rounded form, its branches upright and spreading.  With dark green leaves in summer and less than showy fall foliage, winterberry hollies are easy to ignore most of the year.  But when the berries ripen to red while the leaves are still dark green, winterberry holly brings back memories of the American holly (I. opaca), the spiny-leaved evergreen Christmas holly of my youth.

It is the abundance of berries on each naked branch, not their individual size, that draws attention in winter.  In his notes on wild fruits, Thoreau recorded the size of wild winterberries at seven-sixteenths of an inch in diameter.  Most contemporary sources list the diameter as one-fourth of an inch.  These two measurements likely frame the potential for berry size in the wild population.

Winterberry’s tolerance of drier soils and compacted soils has made it the native deciduous holly of choice for most gardens, yet the species is too big for many gardens, leading to development of more compact cultivars.  In my opinion, the best of the lot is ‘Winter Red’, an upright rounded shrub that grows to about 8 feet in height.  The bright red fruits of this cultivar are slightly larger than those of the species and the fruit set typically heavy.

All hollies, including winterberry, are dioecious, male and female flowers borne on separate plants.  (“Dioecious” means “two houses.”)  One male plant will produce enough pollen to ensure an abundance of berries on several females; a ratio of one pollinator to every nine females is often recommended.   The trick is to plant the right pollinator, as clones selected from different regions of the country have different flowering times.  Just any male will not do.  For example, ‘Southern Gentleman’ is often recommended as the best pollinator for ‘Winter Red’.

I have on my bookshelf a copy of American Plants for American Gardens by Edith Roberts and Elsa Rehmann, published in 1929.   Roberts was a plant ecologist and Rehmann a landscape architect.  Their book speaks of an ever increasing demand for native plants that “fit into the informal, intimate, seemingly unstudied effects that are sought for in many grounds and gardens today where flowers are luxuriantly intermingled, boundaries are freely planted, trees are irregularly grouped and lawns are sometimes left unclipped.”

Gardening in tune with nature is not a new concept.  A garden can feed the desire to feel closer to nature, a place that not only looks like nature but also acts like nature, a place that provides suitable habitat for wildlife, a place that recycles resources, that fosters biodiversity.  Such gardens spring from the marriage of ecology and landscape design.

Growing native shrubs such as winterberry holly is a decision to be intimately involved with the garden, for much of their beauty is subtle.  They are endowed with elusive qualities that we miss unless we look closely, stick our noses or focus our eyes in the right place, in the right season.  You must look closely to appreciate the tiny flowers of winterberry in spring, watch attentively as small native bees and flies forage for a nectar shared with migrating butterflies, including the Painted Lady, the Red Admiral, and the Question Mark.  Winterberry holly also serves as a larval host for the Henrys Elfin Butterfly.

The mystery of the vanishing winterberries will remain unsolved.  Crow, squirrel, chipmunk, fox, who knows?  I like to believe white-footed mice took them for their seeds, scampering up the branches at night to gather the fruits, storing them near near their burrows, perhaps under old tree stumps, for when the snow lies deep over the garden.

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About Reeser Manley

I was born in Laramie Wyoming but moved to the southeast at an early age. I was educated through my B.S. in Biology in the Columbus, Georgia area, then crossed the Chattahoochee River to earn my M.S. in Botany at Auburn University. For the next ten years, I worked as Horticultural Manager for the George W. Park Seed Co. in Greenwood, S.C. At 40 years of age, I decided to return to graduate school and in 1994, I earned a Ph.D. in Horticultural Science from Washington State University, Pullman, Washington. Fast forward through 10 years at university (7 at UMaine, Orono) and you find me teaching high school science in Eastport, Maine, the edge of the world, and writing a weekly garden column for the Bangor Daily News. My new book, The New England Gardener's Year, a Month-by-Month Guide for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, and Upstate New York”, will be published later this year by Cadent Publishing. You can learn more about the book by visiting its Facebook page: http://www.facebook.com/pages/The-New-England-Gardeners-Year/187285218055676.)