American holly (Ilex opaca): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Ilex opaca Ait., holly family (Silvics)
Other names	White holly and Christmas holly (Silvics)
Native status, USDA PLANTS	Native in the lower 48 states; no Canadian status listed
Size, Silvics	Trees of 30.5 m (100 ft) and 122 cm (48 in) in diameter recorded; the national champion in the Congaree Swamp of South Carolina is 30.2 m (99 ft) tall with a trunk diameter of 79 cm (31 in). On sandy coastal sites, 4.6 to 9.1 m (15 to 30 ft)
Green weight of the wood, NRS-38	57 lb per cubic foot, without bark

Native range and where it grows

The Silvics of North America handbook (Agriculture Handbook 654, 1990) says American holly is scattered along the coast from the maritime forests of Massachusetts to Delaware, grows inland into several Pennsylvania counties and abundantly southward through the coastal plain, Piedmont and Appalachian system. The range extends south to mid-peninsular Florida and west to eastern Texas and southeastern Missouri, and corresponds roughly to the combined ranges of loblolly and shortleaf pines. The handbook calls it the hardiest known broadleaf evergreen tree and says cultivars north of its natural range in an Ohio arboretum survived minus 29 degrees C.

Silvics says holly survives on a wide variety of soils, from sandy Atlantic beaches to thin mountain soils up to 915 m (3,000 ft). The largest trees are in rich bottom lands and swamps of the coastal plain, and growth is best on moist, slightly acid, well-drained sites. It says trees will not survive flooding or saturated soils for more than 17 percent of the growing season. At the northern limit of its range, holly dominates some maritime forests: at Sandy Hook, New Jersey, 97 percent of the tree basal area of a 30-ha (74-acre) forest was American holly, with the oldest tree 144 years old and 62 cm (24 in) in diameter.

Flowers and berries

Hollies are dioecious: male and female flowers, similar in appearance, with four to six small white petals, are on separate plants. The handbook says flowering begins as early as age 3, in April in the south of the range and June at the northern limits, with pollination by insects including bees, wasps, ants and night-flying moths. The fruit, commonly called berries, is technically a four-seeded drupe, 6 to 12 mm (0.25 to 0.50 in) across and bright red, orange or occasionally yellow. Fruit ripens from September through December and stays on the tree through most of the winter unless birds or other wildlife eat it. Seed germination is very slow, from 16 months to 3 years in nature. Silvics says at least 18 bird species eat the fruit, including songbirds, mourning doves, wild turkeys and bobwhite, and that large winter-migrating flocks of small birds are perhaps the most important seed dispersers. It notes that despite saponins in the leaves and berries, the plant is not considered poisonous to people or animals.

Growth, shade and fire

The handbook says American holly is very shade tolerant and is seldom dominant, with slow initial growth averaging 1.8 m (6 ft) over 16 years under medium shade. Under intensive culture it records 0.9 to 1.2 m (3 to 4 ft) of height growth a year. It says young trees usually sprout if the tops are removed by cutting or burning. The bark is easily injured by fire and even large trees may be killed by light fires in the understory: three annual fires in a southern pine forest reduced the number of fruit-producing holly trees by 95 percent. It describes the thick evergreen leaves as staying on the tree until the spring of their third year. The handbook's section on the rooting habit reads "No information available."

Wood and uses

Silvics describes the wood as tough and hard but not strong, close grained and moderately heavy, at 40 lb per cubic foot, with a specific gravity of 0.61 oven-dry and 0.50 green. It calls it one of the whitest woods known, with white sapwood and ivory-white heartwood and almost indistinct growth rings. Uses it lists are veneer, limited pulpwood and lumber, and specialty items such as cabinet inlays, brush backs, handles, wood engravings and carvings, and measuring scales, with piano keys and violin pegs when dyed black. It names the foliage with berries, used for Christmas decorations and ornamental planting, as the principal value of the tree. The Wood Handbook table of strength figures does not list American holly, so no strength figures are given here. The green weight is in the NRS-38 table, the same figure used in the log weight calculator.

Damaging agents the handbook names

Harvest and fire. The handbook says the greatest damage to holly trees is indiscriminate harvesting of foliage with berries for Christmas decorating, and that Maryland and Delaware passed laws to protect holly after a roadside market left many trees mutilated. Fire is described as another deadly enemy.
Leaf diseases. The thick evergreen leaves are year-long hosts to many foliage diseases, including 14 leaf spot fungi, six black mildews, two powdery mildews and one rust, few of which threaten tree health but which reduce the value of the foliage. A serious leaf and twig blight caused by Corynebacterium ilicis is recorded in northeastern hollies.
Insects. Nearly 30 species attack holly but only a few are serious: the southern red mite, the native holly leafminer, which can damage foliage severely and cause leaves to drop, the holly midge, which keeps berries green, and several scale insects.
Weather. Twigs and branches can be killed in extreme cold in the north of the range, and roots inundated for several weeks can kill the tree. Holly is more resistant to salt spray than its neighbors in New England maritime forests.

For who takes reports of regulated pests, see reporting a pest in the United States, and pests and diseases by country sets out which ones agencies regulate.