American Holly Trees
9 December 2004
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
As folks decorate their homes for the holiday season one of the most commonly used plants is the American Holly. The first settlers from Europe must have recognized the similarity of this plant to their own Christmas plant, the English holly (Ilex aquifolium), because the American holly (Ilex opaca) has been used for holiday decorations and ornamental plantings ever since.
The American Holly is a relatively small evergreen broadleaf tree. It can attain a height of 40 to 50 feet with a spread of 18 to 40 feet. American hollies are noted for their spiny, evergreen leaves and bright-red berries that mature in autumn. This holly is pyramidal in youth with branches to the ground and becomes slightly more open with maturity, but still maintains roughly a pyramidal shape. Older plants have horizontal branching.
The American holly grows in zones 5 through 8 and is native to Virginia. This plant needs partial shade and well drained, acidic soil with a pH in the range of 3.5 to 6.0. Iron chlorosis is a problem in high pH soils. They are cold tolerant but do not tolerate wind so plant in a location protected from wind.
Suggested uses for this plant include hedge, screen, and specimen plant. It is recommended to plant in spring using trees that have balled and burlapped roots or that are container grown. Since this holly is dioecious, both male and female plants are required for fruit production. Plant one male plant for every 2 to 3 female plants to ensure good fruit set. Only female plants produce berries. Fruit mature in October and persist into the winter. Blooms occur in June and are small white flowers. Male plants flower in groups of 3 or more while female plants have solitary flowers.
Problems for the American holly include irresponsible harvesting of foliage with berries for Christmas decorations, forest fires, a few diseases, and insects. Diseases include various fungal leaf spots, mildews, and a rust. Since the trees are evergreen they provide shelter to a number of insects but only a few true pests. The southern red mite causes a reduction in leaf and twig growth and undesirable foliage color. The native holly leafminer can damage foliage severely, causing leaves to drop prematurely. Several species of scale insects feed on holly, including the holly scale. American Holly also depends on insects, such as bees, wasps, and moths to pollinate its flowers so it is a good idea to identify any insects you find on your hollies before you jump to the conclusion that they are doing damage to the trees.
Holly is pruned in winter, as needed, and can withstand heavy pruning. Of course, the clippings are usually put to good use as holiday decorations.
Over 1,000 cultivars of this plant exist. Desirable characteristics in holly cultivars include annual bearing, large and bright colored fruits, good foliage, and dense habit. American Holly appears to be regionally adapted. Consult local sources, including historic or public gardens, nurseries, and arboreta, regarding cultivars and related species that grow well in your area.
American Holly is a good food source for many animals including Wild Turkey, Northern Bobwhite, Mourning Dove, Cedar Waxwing, American Goldfinch, Northern Cardinal, Eastern Gray Squirrel, White-tailed Deer, Eastern Chipmunk, Meadow Vole, White-footed Mouse, Red Fox, Raccoon, Eastern Cottontail, and Eastern Box Turtle. These animals are beneficial to the species because they help spread the holly seed to grow new trees. Because we have so many of these animals is why you see this tree growing so abundantly in the woods in this area. This tree also is a good nest site for many bird species.
For more information about landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.
Virginia Cooperative Extension will be offering Master Gardener classes in Fluvanna and Louisa counties beginning in January. Please call your local Extension office for more information.