By Ranger Steve Mueller

A winter drive north along the freeway takes you past low wetlands. People often notice the red berried shrubs growing in swamps and bogs. Only the female plants draw attention. It is known as winterberry or Michigan Holly (Ilex verticillata). The plants are dioecious, meaning plants are either male or female. 

The US FWS reports that at least 48 species of birds eat the berries. They are low in fat content so are often avoided until winter food is scarce. This is good for our eyes. We get to enjoy the red splash of color through most of the winter. Mammals like deer and rabbits tend to avoid eating the stems and leaves so if it is planted in your yard, it will grow unabated. During times of scarce food, wildlife will eat it. 

Berries should not be eaten by humans because they are toxic to us. 

The shrub is well adapted to wetlands but also grows in drier upland sandy soils. It grows thick and full but does not draw attention except when fruiting. It will grow taller than a human and spread widely. It grows best when free from crowding by other plants so that makes it ideal as a landscape shrub. 

Planting native species is always the best choice because they have adaptations to the local environment and are more likely to survive. 

The plant is sneaky. Though it grows quite large, the stems, leaves, and even flowers do not draw attention. Leaves are a rich green and shaped similar to cherry leaves. Twigs are tan with small inconspicuous brown buds. Flowers bloom after leaves are present so they are concealed. The male flowers are small and pale. 

They require insects for pollination and subsequent fruit production which means insecticide use should be avoided. Native plants have adaptations for survival without needing use of chemicals. The nature niche flowering period for male and female flowers is quite narrow and limits successful fertilization. 

At Ody Brook we have few winterberries but maybe more than I realize. The male plants blend into the landscape and females only become apparent in winter if they produce red fruits. If the sexes are too far from each other, pollination will not occur and even the female shrubs will not obviously show themselves. 

For holidays, people like to use the red berried stems in decorations. This is fine provided only a few branches are pruned from a shrub. Cutting removes next year’s flowers buds and no fruits will be produced when too many flower bud stems are removed. It is best to enjoy the brilliant red fruits on the live stem where they grow in the neighborhood. 

For many the treat is seeing them in winter wetlands as we drive by.

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.