Winterberry, known botanically as Ilex verticillata, is a winter-fruiting perennial shrub that blooms in spring and throws bright red, orange or yellow long-lived berries on naked branches October through January. A relation of holly, winterberry is grown primarily as a winter garden ornamental in hedging, borders, bedding and containers. It also is widely used as a cut flower and for seasonal decoration.
Plant your winterberry shrubs in the spring in full sun to partial shade whether planted in garden soil or in containers. Provide a nutrient-rich, well-drained soil. After planting, lay down at least a 2-inch thick blanket or organic mulch such as shredded bark or leaf mold, and compost to enrich the soil and prevent moisture loss. Replenish the mulch once a year or when it begins to significantly degrade.
Water your winterberry regularly during its first few years so that the soil is evenly moist. Water deeply in the fall before the ground freezes so the roots have a good base of protection against winter drought. After the shrub is mature at 3 to 4 years of age, usually you can dispense with regular irrigation other than in seasons of drought.
Feed your winterberry shrubs at least once, but not more than twice a year as they are not heavy feeders. Make the first application of a water-soluble, general-purpose fertilizer in the spring and a second application in late summer or early fall to boost winter-fruit performance. Whether using a fast-acting or slow-release formula, apply it over pre-moistened soil at the roots and around the drip line of the shrub. Water thoroughly.
Prune your winterberry with clean, sharp secateurs or long-handled loppers to control the shape and size of the shrub or to harvest fruiting canes. Winterberry does not require pruning for bloom and fruiting, so make cuts that shape and tidy up the shrub to your liking and so that it fits in with its surroundings.