Winterberry: Michigan’s native holly
Michigan holly provides a colorful display in the winter landscape and a late-season food source for birds.
March 10, 2017 - Author: Bob Bricault, Michigan State University Extension
Color in winter is often at a premium in Michigan, but if you look closely even on a gray, winter day, you can find colorful plants in natural areas as well as landscapes. The red and yellow twigs of dogwood shrubs provide color throughout the year. Yellow flowers of native witch-hazel plants appear in late fall, while crabapples, hawthorns and mountain-ash trees have red, orange or yellow fruit well into winter. The one plant that draws my eye across a winter field is the bright red berries of the winterberry, Ilex verticillata, also known as Michigan holly.
A native plant and member of the Holly family, it is found in swampy habitats across the Eastern United States from zone 3 to 9. It is a deciduous holly shrub that can grow 10 feet tall and 10 feet wide. It prefers wet sites with acidic soil. Like other members of the Holly family, it develops bright red fruit. Its real glory begins when the leaves drop from this holly in autumn, leaving a beautiful display of clusters of red fruit.
The long-lasting fruit remains on the plant often into mid-winter and is a food source for robins, mockingbirds, bluebirds and cedar waxwings. Late fall through early winter, I love to drive the back roads along the rolling hills and wetlands of Jackson and Washtenaw counties. On a sunny day, the bright red berries are displayed like holiday decorations against the blue sky.
Winterberry is generally a dioecious plant, which means it has male and female flowers on separate plants. For the female flowers to be pollinated and produce berries, it requires the pollen from a male plant. Michigan State University Extension recommends at least one male plant for every six to 10 female plants.
The size of the common form of this shrub and the need for multiple plants for fruit production would require a large space not found in many urban landscapes. Fortunately, the development of numerous cultivars has produced smaller plants that bring the beauty of the winterberry to urban landscapes. ‘Red Sprite’ is a compact form that ranges from 3 to 5 feet high with the same bright red berries of the common form found in nature. I have seen this cultivar growing in a landscape in Genesee County.
The numerous cultivars available are a testament to the desire to find a winterberry that fits into smaller landscapes. Cultivars vary in size of the plant and the fruit, amount of fruit produced and fruit color, ranging from deep red to reddish orange and even a yellow fruit selection with a pinkish orange tint.
The varying times these cultivars bloom require a male pollinator plant that produces pollen to coincide with the development of the female flowers. The University of Connecticut’s Plant Database provides a list of Ilex verticillata cultivars and pollinator plants.
Winterberry requires moist acidic soils, which may limit its use to very specific sites in Michigan, but what a splendid plant to use, providing color in winter and a native food source for over-wintering birds. As winter passes into spring, keep in mind the winterberry plant as you begin the annual spring trek to local garden centers.