Editor's note: This is the first of a two-part story. Part 2, about yaupon and deciduous hollies, will be published Dec. 22.
It adorns mantels, brightens wreaths, and is celebrated in song throughout the month of December. Quiet and unassuming the rest of the year, American Holly (Ilex opaca) lends tradition and function to the Lowcountry landscape wherever it grows.
According to the U.S. Forestry Service Silvics Manual, when the pilgrims landed in Massachusetts in 1620 they were greeted by woods filled with American holly.
This holly reminded them of the familiar English holly (Ilex aquifolium) that they were accustomed to using in religious celebrations in England and Europe. Americans still rely on this familiar plant for landscaping, decorating, and woodworking uses today.
American holly, also known as white or Christmas holly, is native to North America and grows along the eastern seaboard, south to Florida, and as far west as Texas. There are more than 400 species or types of hollies worldwide and there are more than 1,000 cultivars of American holly, making this one popular native plant.
The red berries, which ripen from October to December, serve as an important food source for many migrating songbirds, as well as wild turkey and mammals such as squirrel and deer. The flowers serve as an important nectar source for honeybees in making their delicious honey. Pollen is also transferred by wasps, ants, yellow jackets, and night-flying moths. Birders have noted that flocks of cedar waxwings have been known to quickly strip a tree of its berries in minutes!
These slow growing evergreens are one of the largest hollies, reaching mature heights of 15-60 feet and 15-20 feet wide. While their berries are usually red, sometimes orange or yellow berries occur.
Their natural form is a pleasing pyramidal shape that makes them popular landscape specimens.
Because they are also tolerant of urban conditions, they make wonderful street and parking lot trees. They are great for creating living fences and sound dampening barriers when they are planted with ample space to grow.
American holly is tolerant of a wide range of growing conditions and soil types. They have few if any disease or insect problems and are so adaptable they even tolerate salt spray. Found growing in the understory of pine and hardwood forests naturally, American hollies are shade tolerant but growth will be slowed and fruiting will be less showy in the shade. Trees grown in the shade will develop larger leaves in order to capture sun filtered through high canopies.
Nearly all hollies, including the American holly, are dioecious containing male (staminate) and female (pistillate) flowers on separate plants. When purchasing cultivars of hollies, it is important to note that a pollinizer, or a plant that supplies pollen, is required for good berry production.
For hollies in particular, the pollinizer does not have to be of the same species as the holly requiring the pollen. For example, American hollies provide pollen for hybrids such as 'Foster' (Ilex x attenuata 'Fosteri') and 'Savannah' (Ilex x attenuata 'Savannah') and native deciduous hollies like Possumhaw holly (I. decidua).
Typically, one male pollinizer such as 'Jersey Knight' is recommended to supply enough pollen for up to five female trees in the landscape. Since American holly is so widespread, wild specimens in nearby woods often provide ample pollen to make berries. If the holly berry production is low on plants in your landscape, lack of pollination might the culprit and a male plant should be planted nearby.
The straight species of American holly have leaves which are lighter green and are slightly duller in color than newer cultivars selected for their glossy, deep green foliage. The female cultivars 'Amy', with large glossy spiny leaves and large plentiful red fruit, or 'Dan Fenton', with round, spiny, glossy dark green leaves are newer varieties and considered a "significant improvement over most American hollies" by the Auburn Cooperative Extension service.
More unusual cultivars for the more adventurous gardener include 'William Hawkins' a male holly with long, spiny strap-like leaves, or 'Yellowberry' a female with bright yellow berries.
Amy L. Dabbs is the urban horticulture extension agent and Tri-County Master Gardener coordinator for the Clemson University Cooperative Extension. Send questions to firstname.lastname@example.org.