Homegrown Habitat, January 2024: American Holly
Wildlife of all sorts love the berries of the American holly. Deer however prefer a more palatable meal than the glossy, spined leaves. Photo by Gilles Carter.
Connecticut Audubon’s habitat specialists have such high regard for American holly that they’ve planted it extensively at the Milford Point Coastal Center and the Smith Richardson Sanctuary in Wesport—more than 100 trees at the latter, in expectation of a magnificent grove a generation from now. And when they consult with other organizations on habitat restoration, they always recommend American holly.
Sarah Middeleer, our Homegrown Habitat columnist, thinks highly of it as well. Read her column, consider planting it on your property, and email her if you have questions: homegrown@ctaudubon.org.
When the Pilgrims arrived in what is now called Massachusetts, they encountered pyramidal evergreen trees with spiny leaves and red berries that reminded them of a tree back home called English holly (Ilex aquifolium), a symbol of Christmas for centuries in England and Europe. Thus the American holly (Ilex opaca), also known as white holly for the color of its wood, was immediately bestowed with similar reverence and symbolism, which it still retains.
American holly is native primarily to southeastern lowlands, but its natural range extends into coastal Massachusetts south to central Florida and west to West Texas, southeastern Missouri, West Virginia, and parts of Pennsylvania. It is the most cold-hardy of our native broad-leaf evergreens, tolerating minus 10 degrees in West Virginia and even minus 29 degrees in a northern Ohio arboretum, north of its native range.
American Holly will tolerate a range of soils (preferably acidic) but not prolonged soil saturation. In the northeastern portion of its range it is found on sandy coastal soils or dry gravelly soils farther inland. Holly is remarkably shade tolerant, naturally growing as an understory tree beneath pines or hardwoods. In our region it commonly grows in association with red maple (Acer rubrum).
Although the national champion American holly is 99 feet tall (located in the Congaree Swamp of North Carolina), in cultivation in the Northeast, it typically grows slowly to a height of 15 to 35 feet but can be pruned to stay shorter. It has a spread of 10 to 20 feet.
Connecticut Audubon has planted American holly at several habitat restoration projects. This is one of about 100 trees planted at the Smith Richardson preserve in Westport. Photo by Gilles Carter.
Holly flowers are small and greenish- to creamy-white, appearing May to June. Male flowers have stamens with yellow pollen, while female flowers have a green ovary in the center. The male flowers are fragrant and thus attract pollinators. They are pollinated by Henry’s Elfin butterflies and bees.
The striking red fruits are technically known as pyrenes, or four-sided drupes. They are produced only on female trees, so try to purchase trees from a knowledgeable nursery where they can vouch whether their trees are male or female. Or plant more than one in the hope that at least one of them will be female. Having a male partner in close proximity will help to boost pollination and fruit yield. Despite holly’s shade tolerance, fruiting will be most abundant in full sun.
At least 18 species of birds, including American Robin, Eastern Bluebird, Gray Catbird, Hermit Thrush, Northern Mockingbird, and Northern Cardinal eat American holly fruit, although it is also enjoyed by deer and small mammals. Flocks of Cedar Waxwings and American Goldfinches have been known to strip an American holly of its entire fruit crop in short order. The holly foliage is said to be resistant to deer.
Forty-one species of butterflies and moths, including the charismatic polyphemus and io moths and Henry’s Elfin butterfly, utilize native hollies as host plants, where they will lay eggs. The resulting larvae are an extremely valuable food source to birds, especially during nesting season.
The many garden uses for American holly include using it as a specimen or as an understory component in a woodland garden, perhaps along with flowering dogwood and common witchhazel. Consider it also for a privacy screen, perhaps in combination with native conifers. American holly will be happier if it is protected from harsh winter winds and hot afternoon sun in the summer. It rarely needs pruning, but some gardeners prefer to cut off the lower limbs in order to expose the interesting gray bark, which is often covered in lichens. But its branches naturally extend to the ground, enhancing its shelter-giving potential to wildlife.
American holly wood is white and is used for veneer and specialty items such as inlays, handles, and wood engravings. When dyed black, holly wood resembles ebony and is used for piano keys, violin pegs, and fingerboards. Native Americans made tea from American holly to treat coughs and used its berries to make buttons.
We love to hear from readers – please send comments and questions to homegrown@ctaudubon.org
RESOURCES
Heather McCargo and Anna Fialkoff, Native Trees for Northeast Landscapes, Wild Seed Project, 2021
https://www.backyardecology.net/american-holly/
https://plants.ces.ncsu.edu/plants/ilex-opaca/
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=k640
https://www.nwf.org/NativePlantFinder/Plants/1722
https://www.clemson.edu/cafls/demo/plant_profiles/ilex-opaca-american-holly.html
https://perec.science.gmu.edu/native-plants/american-holly/
https://www.exploringbirds.com/posts/birds-attracted-to-american-holly
https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/ilex/opaca.htm
