The winterberry tree (Ilex verticillata), sometimes also known as the common winterberry, black alder, coralberry, Christmas berry and winterberry holly, is prized as an ornamental across U.S. Department of Agriculture plant hardiness zones 4 through 8 for its graceful form along with the attractive red berries that continue this plant into the winter.
Form and Habit
Winterberry is a large shrub or small tree that may grow up to 20 feet tall. It is multi-stemmed and tends to sucker readily, forming large clumps. The winterberry features a rounded, vase or upright oval form and, generally, an appealing, symmetrical canopy, although young plants have a more irregular contour. Various winterberry cultivars offer a dwarfing tendency and a more formal look than the standard. Winterberry is deciduous, meaning it loses its leaves each year.
Foliage, Flowers and Fruit
Winterberry branches look twiggy and dark grey; they are very visible in winter when they are leafless and supporting the grasses. Winterberry flowers, which appear in summer, are inconspicuous and white. These flowers develop into berries that begin green, then mature to become glowing red. The berries are attractive to birds and remain on the leafless plant well into winter. The leaves of the plant measure around 3 inches long and 1-1/4 inches wide and are green to dark-green throughout the growing season before they turn yellow-green and fall in autumn. Winterberries are either male or female; only the females produce fruit. A winterberry with male flowers must be implanted near female plants; they must have overlapping bloom periods so as to fruit.
Winterberry will grow in full sun or partial shade. It prefers an acidic loamy or sandy soil that provides regular moisture but is also well-drained. Winterberry is tolerant of compacted soil and seasonal flood, as well as periods of drought when it’s established. It may be cultivated as a bonsai or container plant or used in the landscape as a specimen or hedge.
If the winterberry is increased in a turf area, mulching the region under the canopy prevents unsightly, thin turf and lessens accidental mechanical harm to the drooping stems. Only pruning to correct any damaged or out-of-place branches or stems is required if the winterberry has ample room to spread. If the soil has too high a pH or is alkaline, the specimen may develop iron chlorosis. Regular moisture is also significant, as periods of drought may lead to fruit drop.