American holly is a small- to medium-sized evergreen tree or shrub, with short, crooked branches and a rounded or pyramidal crown.
Leaves are alternate, simple, thick, leathery, elliptical, 1½ to 3 inches long; wavy-edged with large, sharp, spine-tipped teeth; upper surface dark green, dull, smooth; lower surface paler green, smooth to somewhat hairy.
Bark is thin, brown to grayish-brown, with warty projections.
Twigs are stout, green to light brown or gray, covered with fine, rust-colored hairs when young, smooth later; pores small.
Flowers May–June, in short-stalked clusters, male and female flowers on separate plants or sometimes on the same plant; petals 4, white. Male flowers in clusters of 3–9; female flowers single or in groups of 2–3.
Fruits in October; bright red-orange berries, ¼ inch in diameter; often remaining on tree over winter.
Similar species: Four species of hollies (genus Ilex) can grow without cultivation in Missouri's wild habitats. American holly is the only one with the leaf blades tipped with a spine and the margins of the leaf blades usually also with spine-tipped teeth. Our other hollies lack spines on the leaves. Our other two native hollies are possum haw or deciduous holly (I. decidua), whose relatively thin leaves drop off in winter, and winterberry or black alder (I. verticillata), whose leaves are saw-toothed but not spine-tipped. Yaupon (I. vomitoria), our fourth hollly, is occasionally cultivated here as an ornamental shrub, and it has been collected only once in Missouri, growing wild along a railroad — in 1897.
Height: up to 50 feet.
As a native, rare in our state, living only in southern and eastern regions. Various cultivars are planted as ornamentals statewide, but this species does not survive cold winters well.
Habitat and Conservation
To find American holly in the wild, visit Crowley's Ridge in southeastern Missouri, where it grows on that ridge's lower slopes in sandy-gravelly soils that remain moist from seepage. If you are planting American holly as an ornamental, keep its native habitat in mind, and provide it with moist, well-drained sandy soils with plenty of room for growth and partial sun.
Because of its exacting habitat requirements and loss of such habitat in our state, this species is rare in Missouri — in the wild. But hundreds of cultivated varieties are planted by landscapers throughout America.
Because of its attractive, evergreen leaves and bright red berries that persist at Christmastime, this plant is associated with Christmas ("holly" is an ancient variant of the word "holy"). It's a popular landscaping shrub, it provides good windbreaks, and its incredibly white wood is prized by carvers.
After frosts have rendered the berries more palatable, dozens of species of birds consume the fruit. This plant also offers protection to many types of animals, including birds.