Common Name: Winterberry, winter hollyberry, hollyberry
1 - 2 ft height at sale, bare root
Native to Vermont
Sourced from MI
Northern Holly. Green lead. No berry guaranteed.
Recommended Spacing (ft) 6 - 15 Mature Width (ft) 3 - 15 Mature Height (ft) 3 - 15 Growth Rate (in/yr) 13 - 24 Pollination Needs Dioecious - male must be located near female to pollinate Bloom Time June Ripens/Harvest Early fall
5.5 - 6.5 Soil Type Loamy, Sandy, Silty Loam Soil Moisture Moist, well-drained Sun Preference Full Sun, Partial Shade
Winterberry holly (Ilex verticillata) is a deciduous shrub that is native to the eastern U.S. It is a great addition to the landscape because it produces bright red berries that persist through the entire winter and into spring. These shrubs are dioecious, which means that they have specific genders, either male or female. The right male variety must be located near a female plant to ensure the female plant is pollinated to produce berries.
Winterberry holly leaves are dark green and elliptical, about two to three inches long. Greenish-white flowers appear on female plants in spring, which, if properly pollinated by a male plant, produce a dense crop of bright red berries in the fall. A slow-growing shrub with a rounded upright growth habit, winterberry typically grows 3 to 15 feet tall and readily suckers and spreads to form large thickets. It is generally planted in late summer to early fall, though spring planting is usually successful, as well. Winterberry holly is often associated with the Christmas holiday season and their berry-laden stems are used to add color to evergreen arrangements.
Winterberry holly is toxic to people, dogs, cats, and horses.
Unlike other familiar holly shrubs, winterberry holly is a deciduous shrub rather than an evergreen. Although one might view this as a drawback, it proves to be a beneficial trait because it allows the exciting display of red berries to be very visible during the winter months. All the attention is drawn to the plant's fruit without foliage to obstruct the view. Not only do the bright berries add color to winter landscapes, they also lure in birds that love to feed on the prolific red berries.
In nature, winterberry holly shrubs grow naturally in wetland areas, which makes them ideal for routinely moist or poorly drained areas of a home landscape where little else will grow. However, they'll also grow in a variety of conditions, if they receive enough moisture. Winterberry is generally pest- and disease-resistant but can be susceptible to leaf spots and powdery mildew, which are rarely serious.
Winterberry holly is a dioecious plant, which means that plants are gender specific, either male or female. Because only fertilized female plants will produce a wonderful display of berries, at least one male winterberry plant must be planted within 40 to 50 feet of a female for cross-pollination to occur. Generally, a single male shrub can pollinate six to ten female shrubs. When purchasing a winterberry holly, it is key that the male plant blooms at the same time as the female. Most quality garden centers include the gender on the plant tag so that you purchase the right pairs of plants.
Winterberry holly will do well planted in a location with full sun to partial shade. To ensure ample flowering and fruiting, plant the shrub where it receives at least six to eight hours of sunlight per day.
This plant adapts to both light and heavy soils but performs best in acidic loam with a good level of organic material. It does poorly in neutral to alkaline soil, which can cause fatal chlorosis (yellowing of the leaves). Feeding it with a fertilizer designed for acid-loving plants can help modify soil pH levels if a soil test reveals soil that is neutral or too alkaline.
Winterberry prefers fairly wet conditions. Do not plant it in dry soil or a dry climate unless you are willing to water frequently. This plant will require at least one inch of water per week, either through rainfall or irrigation.
Temperature and Humidity
Winterberry has a good tolerance for all temperature and humidity conditions across its hardiness range, though it does not do well in conditions of prolonged dryness.
Winterberry holly usually doesn't require feeding unless growth is very slow. Where needed, 1/2 cup of balanced 10-10-10 fertilizer applied each spring usually is sufficient. Feeding with a fertilizer designed for acid-loving plants can help modify soil pH levels if a soil test reveals soil that is neutral or too alkaline.
Because the flowers (and resulting berries) appear on new growth, winterberry holly should be pruned to shape in early spring, just before new growth appears. Pruning is recommended because these shrubs not only grow tall, they also sucker profusely if not controlled. Remove up to (but no more than) 1/3 of the branches each year. Target the oldest branches, and prune them down to ground level.
How to Get Winterberry Holly to Bloom and Produce Berries
Winterberry holly is primarily planted for its abundant and colorful berries, so it makes sense that you'd want to ensure the best show possible. A few factors directly impact how vigorously your winterberry holly will bloom, the first being the presence of compatible male and female varieties.
Both genders will produce small green-white flowers in late spring which will eventually turn to berries on female plants if properly pollinated. To identify the female from the male shrubs, look at the center of their flowers: female plants will have a small green nub in the center while male plants will have pollen-bearing anthers.
Regardless of gender, winterberry holly shrubs require pruning at the proper time of year in order to ensure a crop of berries. The plant blooms on old wood, which means the only time you should prune it is sporadically in the winter while the berries are still on the bush. But the best option is to plant the shrub somewhere where it can grow freely—that way, you don't risk pruning off future blooms and berries.
If your winterberry does not produce flowers or berries, it could be a gender issue: the right female and male pairs are not located close enough to each other. If you're still not seeing berries or flowers on your shrubs—assuming all other care requirements are met (including the proper amount of sunlight and water)—the problem could lie in the age of the shrub. Winterberry hollies only fruit when they're well established, which can mean as many as two to three years in the ground before you're granted a showy display.
[description from thespruce.com]