Ilex opaca
American Holly
Mature Size, Growth, Longevity
Average mature size is 40-50 (60)' tall and 18-40' wide, with an upright form, conical or pyramidal in youth, with age developing an open, irregular habit, with high branches at wide angles. Slow to moderate growth rate. Has a "medium" lifespan, with the genetic potential to live 100-150 years.
Native Range
Kentucky Native — Native range Massachusetts to Florida, west to Missouri and Texas. Introduced in 1744.
Flower and Fruit Details
Spring flowers are dull white, 4-lobed, dioecious, male in cymes, female 1-3 on a peduncle. Fruit is a berry-like, dull, red, rounded drupe, 1/4-1/2" diameter, on female plants, with 4 pits. Fruits attract bluebirds, thrushes, woodpeckers, catbirds, thrashers, mockingbirds, and others. Raw berries are toxic to humans.
Leaf and Bark Features
Evergreen: Leaves are simple, broadleaf evergreen, 1.5-3.5" long, and half to three-quarters that wide, alternately arranged, dark green, spiny with large teeth, and leathery. Smooth, light gray bark.
Culture and Care
Needs a nearby male holly to get fruit on female plants. Needs moderately fertile, moist, loose, acid, well-drained soil. Tolerates some shade, but sun is best for denser plants and more fruits. Avoid dry, windy, wet sites. Pollution tolerant. Zone 5-9. Holly leaf miner and scale insects can be a problem, as well as powdery mildew disease, spine spot and leaf scorch. Chlorosis may occur in alkaline soils.
Strengths, Weaknesses, Other Facts
The broad, evergreen leaves and colorful fruits provide winter food and shelter for songbirds. The leaves provide larval food for Henry's elfin butterfly. The American Holly is more deer-resistant than most of the other hollies. Good wildlife value. 4-season interest: Spring, Summer, Fall, Winter. There are over 1,000 cultivars of American Holly. For best fruit set, plant one male nearby for every 3 females. Native Americans preserved holly berries for use as decorative buttons, which were highly prized trade items. State tree of Delaware.
Suggested Uses
Makes a good specimen plant, due to its large, evergreen form and colorful fruits on the female plants. Good where a larger broadleaf evergreen is needed. Also works well as a group planting. May also be used as a hedge.
Taxa and Plants of this Species at BCA
The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.
Ilex opaca 'Canary' // Canary American Holly
Tree. A female form, with vivid yellow to orange-yellow fruit. It produces an abundance of fruit. Leaves are light green with small spines, or may be dark olive-green, keeled, curved, with obtuse base, 2.75-3.0" long, and half as wide. Introduced in 1939 from the Great Smoky Mountains of Western North Carolina and registered with the American Association of Nurserymen.
BT005672Ilex opaca 'Cave Hill #1' // Cave Hill #1 American Holly
Tree. A female form, 25-40' tall and 20-30' wide. This cultivar was selected for its lustrous, dark olive-green, keeled leaves with short spines (4-5 on each side), and a dense branching habit. Fruits are abundant, 5/16", cardinal-red to vivid reddish-orange berries. A Theodore Klein introduction, before 1940, selected from plants at the Cave Hill Cemetery in Louisville, KY.
BT005673Ilex opaca 'Chief Paduke' // Chief Paduke American Holly
Tree. A female form with dark olive-green leaves, broadly elliptic, 3" long by 1.5" wide, keeled, curved, with 1-3 spines on each side, on upper 2/3 of leaf, petiole over 0.5". Fruits vivid reddish-orange, ellipsoid, nearly 0.5" in size. Original plant in cemetery in Paducah, Kentucky. Selected in 1959.
-- not currently in our collection --Ilex opaca 'Judy Evans' // Judy Evans American Holly
Tree. Excellent, dark, olive-green, glossy foliage, broadly elliptic, to 2.5" long and 1.75" wide, keeled, curved, 4-6 prominent spines on each side of leaf, dark petioles, 5/16" long. Fruits vivid red, globose, 5/16" diameter. Compact, very dense, broad-pyramidal to conical habit. Grows to 40' in height. Named (after his niece) and introduced by Theodore Klein in 1940. Originated in Cave Hill Cemetery, Louisville, KY.
BT005671Ilex opaca 'Maryland Dwarf' // Maryland Dwarf American Holly
Shrub. A dwarf cultivar, with a low, broad-spreading, mounded habit, broader than tall. Makes a good shrubby groundcover or specimen. Grows 3-5' tall and 6-8' wide. A female form with sparse fruit production. Fruits are few, vivid red, globose, 5/16" diameter. Leaves are dark olive-green, oval, to 2" long and 1 3/16" wide, keeled, curved, with 3-4 small spines on each side. Selected and introduced in 1942.
-- not currently in our collection --Ilex opaca 'Old Heavyberry' // Old Heavyberry American Holly
Tree. Vigorous selection to 15-25', with a round to conical habit. Has large, dark olive-green leaves, which are broadly elliptic to oval, to 4" long and 2" wide. Leaves are keeled and curved, with an obtuse base and a dark petiole. Good winter foliage. Hardy. Female form with heavy fruit set and excellent winter hardiness. Large, vivid red fruits are globose, 11/32" diameter. Deer resistant. Dark green foliage color holds well even in severe winter.
BT005676