Winterberry, Ilex verticillata, is a deciduous holly where it typically occurs in swamps, damp thickets, low woods and along ponds and streams. This is a slow-growing, deciduous shrub with an upright-rounded habit that typically grows 3-12’ tall. In the wild, it often suckers to form large thickets or colonies. Elliptic to obovate, toothed, dark green leaves. The blooming period occurs from late spring to early summer. Each fertile female flower is replaced by a globoid berry about ¼-inch across that becomes bright red at maturity. Individual berries contain 1-2 smooth bony seeds that are ovoid-oblongoid in shape. Vegetative offshoots are not produced by the woody root system. The leaves turn black when exposed to frost during the fall.
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.
Habitats include bottomland woodlands, damp woodland borders, sandy flatwoods, soggy thickets, swamps, forested bogs and shrub bogs, and rocky banks of rivers. This shrub is found in both sandy and non-sandy woodlands, swamps, and thickets.
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.