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. This is a deciduous shrub with an upright-rounded habit that typically grows 3-12’ tall. Elliptic to obovate, toothed, dark green leaves (2-3” long). Leaves may turn attractive shades of maroon in the autumn. Small, greenish-white flowers appear in the leaf axils in late spring. Flowers 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.
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. 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. Hardy in zones 3-9.
Growing Instructions for the Winterberry
The seeds have a period of dormancy. They can be planted outdoors in the fall or winter for spring germination or they can be cold stratified to simulate winter conditions and to break their dormancy at any time of the year. 1. Scarify the seeds by nicking or sanding the seed coat. The seeds can be sanded with sandpaper, a nail file or an emery board. 2. Soak the seed in water for 24 hours. 3. Place the seeds in a plastic bag and seal it. Store the bag in a refrigerator for two months. 4. The seeds like moist, well-drained soil. Prepare a mixture of half potting soil and half sand, perlite or vermiculite. Put the soil in a pot. Water the mixture so that it is moist but not wet. 5. Sow the seeds 3/8 of an inch deep. 6. Water the container and leave it to drain. 7. Put the pot in a shady area. 8. Water the pot regularly so that the soil is moist but not wet. 9. The seedlings can be transplanted when they are a few inches tall.