From late fall through winter Ilex verticillata produces a grand display of bright red berries that persist and light up its branches long after all of the leaves have fallen. Commonly called winterberry, but also known as Michigan holly or swamp holly, this is a deciduous type of holly for cold climates.
They perform best in full sun and acid moist soils. Therefore, they need to be watered and given acid fertilizer in July and August if there has not been good rainfall. Winterberries flourish best in zones 3 through 9.
Only the female winterberry plants produce the colorful berries, therefore, gardeners should plant one male near 3 to 5 females to ensure good pollination and fruiting. In a large planting it is best to include both early and late blooming male shrubs to maximize pollination of the females.
Some different variations of winterberry for pollination purposes are:
- ‘Jim Dandy’: a slow growing dwarf male useful for pollinating early flowering females such as:
- ‘Red Sprite’: a popular dwarf female maturing to less than 4 feet tall bearing large red fruits.
- ‘Sparkleberry’ is a taller variety and it matures to 12 feet. It has the additional bonus of bearing dark red berries that often persist until spring.