Common Name: winterberry
Type: Deciduous shrub
Family: Aquifoliaceae
Zone: 3 to 9
Height: 4.00 to 6.00 feet
Spread: 6.00 to 8.00 feet
Bloom Time: May to June
Bloom Description: Greenish-white
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Hedge, Rain Garden
Flower: Insignificant
Attracts: Birds
Fruit: Showy
Other: Winter Interest
Tolerate: Erosion, Clay Soil, Wet Soil, Air Pollution
Culture
Easily grown in average, acidic, medium to wet soils in full sun to part shade. Adaptable to both light and heavy soils, but prefers moist, acidic, organic loams. Good tolerance for poorly drained soils including wet boggy or swampy conditions (this species is native to swampy areas of Eastern North America). Winterberries are dioecious (separate male and female plants). Only fertilized female flowers will produce the attractive red berries that are the signature of the species. Generally one male winterberry will be sufficient for pollinating 6-10 female plants. Flowers appear on new growth. Prune to shape in early spring just before new growth appears.
'Ooserwijk' is a female cultivar which needs a male pollinator to produce the attractive bright berries which are the signature of the winterberries. Male pollinator must be a shrub whose flowers bloom at the same time (I. verticillata 'Southern Gentleman' is recommended). One male winterberry will be sufficient for pollinating 6-10 female shrubs. Prune to shape in early spring just before new growth appears.
Noteworthy Characteristics
Ilex verticillata, commonly called winterberry, is a deciduous holly that is native to eastern North America where it typically occurs in swamps, damp thickets, low woods and along ponds and streams. The form of this plant found in Missouri is Ilex verticillata var. padifolia, which occurs in “shut-ins”, granite rocky stream beds and sandstone bluffs in only 4 counties in the southeastern part of the state (Steyermark). This is a slow-growing, deciduous shrub with an upright-rounded habit that typically grows 6-12’ tall. Mature specimens in the wild can reach upwards of 15'. Often suckers to form large thickets or colonies. Elliptic to obovate, toothed, dark green leaves (2-3” long). Fall color is usually negligible, but in some years leaves may turn attractive shades of maroon. Relatively inconspicuous greenish-white flowers appear in the leaf axils in late spring. Flowers, if properly pollinated, give way to a crop of bright red berries (1/4” diameter) in late summer to fall. Berries are quite showy and will persist throughout the winter (hence the common name) and often into early spring. Berries provide considerable impact and interest to the winter landscape.
Genus name comes from the Latin name Quercus ilex for holm oak in reference to the foliage similarities (holm oak and many of the shrubs in the genus Ilex have evergreen leaves).
Specific epithet from Latin means whorled in reference to the arrangement of sessile fruits in pseudo-whorls around the stems.
Common name comes form the quite showy berries that will persist throughout the winter and often into early spring.
‘Oosterwijk’ is sold as a female cultivar. It typically matures to 6’ tall and to 8' wide. It is noted for its dense, heavy fruiting of bright red berries (to 1/4") in fall, with good retention of the fruit throughout winter. Lustrous dark green leaves (to 3” long) turn yellow-bronze in fall. Relatively inconspicuous greenish-white flowers appear in the leaf axils in late spring. 'Oosterwijk' is commercially grown in Europe for the marketing of berry-laden cut branches as Christmas decorations.
Problems
No serious insect or disease problems. Occasional disease problems include leaf spots and powdery mildew. Plants do poorly in neutral to alkaline soils where they are susceptible to chlorosis (yellowing of leaves) and often die.
Uses
Year round interest, highlighted by the showy display of red berries in winter. Mass or group in shrub borders, foundations, native plant areas or bird gardens. Hedge. Excellent shrub for moist soils in low spots or along streams and ponds. Although an attractive shrub, the species is infrequently sold in commerce because of the many excellent cultivars which generally produce showier flowers and larger, more abundant fruit.