Can hollies be successfully grown in Iowa?
American holly (Ilex opaca) and English holly (Ilex aquifolium) are prized for their glossy, green leaves and brightly colored fruit. Sprigs of both hollies are often used in wreaths, centerpieces, and other Christmas decorations. Unfortunately, American and English hollies are not reliably cold hardy in Iowa. However, winterberry (Ilex verticillata) and Meserve hybrid hollies (Ilex x meserveae) can be successfully grown in the state.
Hollies are dioecious. Dioecious plant species produce male and female flowers on separate plants. Only female holly plants produce the red, berry-like fruit. However, a male plant is required for pollination and fruit set.
While most hollies are evergreen, winterberry is deciduous (loses all of its leaves in fall). Winterberry grows 6 to 10 feet tall. The fruit on female plants turn bright red in fall and persist into winter. (Birds usually devour the fruit by mid-winter.) Excellent fruiting varieties include ‘Sparkleberry,’ ‘Winter Red,’ ‘Afterglow,’ 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. 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 hollies 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). Meserve hollies are variable in height. Most varieties grow 5 to 10 feet tall. They are hardy to -20 degrees Fahrenheit (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.