When we think of holly, the image that comes to mind is an evergreen shrub with red berries and dark green, glossy leaves that have sharp points. Sprigs of both American holly (Ilex opaca) and English holly (Ilex aquifolium) are often used in wreaths, centerpieces, and other Christmas decorations. Unfortunately, most holly species, including American and English, are not reliably hardy in Iowa. However, there are a few hollies can be successfully grown in the state.
Flowering and Fruiting Considerations
The colorful red berries are one of the prized ornamental characteristics of hollies. However, if you wish to have good fruit set it is important to understand that these species are dioecious.
Dioecious plant species produce male and female flowers on separate plants. The flowers on male plants produce pollen. Female flowers develop into fruit when properly pollinated.
The flowers of all holly species are small and inconspicuous. Hollies are also dioecious. Only female plants produce attractive, berry-like fruit. When planting hollies, a male cultivar must be planted in the same general area as the female hollies for pollination and fruit set. One male plant is usually adequate for several female plants.
Winterberry
While most hollies are evergreen, winterberry (Ilex verticillata) is deciduous (loses all of its leaves in fall). Winterberry grows 6 to 10 feet tall. The fruit on female plants turns bright red in fall and persists into winter. Birds usually devour the fruit by mid-winter.
Excellent fruiting varieties include ‘Sparkleberry,’ ‘Winter Red,’ ‘Afterglow,’ 'Winter Gold,' and ‘Red Sprite.’ ‘Jim Dandy’ is a good pollinator for ‘Afterglow’ and ‘Red Sprite.’ ‘Southern Gentleman’ pollinates ‘Winter Red’ and ‘Sparkleberry.’
Winterberry performs best in moist, acidic soils. In alkaline soils, winterberry leaves may be yellow-green. This condition is referred to as chlorosis and is due to a lack of chlorophyll in the leaf tissue. Chlorosis can be prevented by adding large amounts of Canadian sphagnum peat to the soil when planting. Incorporating Canadian sphagnum peat into the soil helps lower the soil pH. Plants can be grown in partial shade to full sun. Best fruiting occurs in those areas that receive at least six hours of sun.
Meserve Hybrid Holly
Meserve hybrid hollies (Ilex ×meserveae) are evergreens. ‘Blue Prince,’ ‘Blue Princess,’ ‘Blue Boy’ and ‘Blue Girl’ have dark, bluish-green foliage and are often referred to as blue hollies. The female varieties have colorful red fruit. Other attractive Meserve hybrids include China Boy®, China Girl®, Castle Spire® (female), and Castle Wall® (male).
Occasionally you can find shrubs with both male and female plants planted next to each and allowed to intertwine and grown together. Planting these containerized shrubs means you will get fuit on each plant - although portions of the plant (the male portions) will not have fruit.
Meserve hollies are variable in height. Most varieties grow 5 to 10 feet tall. They are hardy to -20°F (USDA Hardiness Zone 5). In Iowa, Meserve hollies perform best in the southern half of the state. Meserve hollies are susceptible to desiccation injury from the sun and dry winds in winter. When selecting a planting site, choose a protected location, such as on the east side of a building.
Inkberry
Unlike many hollies, inkberry (Ilex glabra) is not grown for its fruit. Inkberry is an evergreen holly with dark green foliage and black, berry-like fruit. Plants grow 6 to 8 feet tall. The overall look of this shrub is reminiscent of boxwood.
While inkberry is evergreen, in Iowa it will oftentimes lose its leaves in winter during extreme cold. It is best used in protected areas as an accent or specimen plant in the home landscape.
'Compacta' is a dwarf female variety that grows 3 to 4 feet tall. 'Nordic' is a compact, rounded shrub with lustrous dark green foliage. It grows 3 to 4 feet tall. Inkberry requires a moist, acid soil in partial shade to full sun.
Holly and Holidays
Holly was considered sacred by the ancient Romans. Holly was used to honor Saturn, god of agriculture, during their Saturnalia festival held during the winter solstice. The Romans gave one another holly wreaths, carried it in processions, and decked images of Saturn with it. During the early years of the Christian religion in Rome, many Christians continued to deck their homes with holly to avoid detection and persecution by Roman authorities. Gradually, holly became a symbol of Christmas as Christianity became the dominant religion of the empire.
More Information
- Broadleaf Evergreen Shrubs for Iowa
- Can hollies be successfully grown in Iowa?
- Mistletoe and Holly During the Holidays
- Caring for Holiday Plants
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