Western poison ivy grows as a knee-high shrub statewide. We are now seeing patches of it that have begun displaying beautiful yellow and red autumn foliage colors. The shiny leaves always have three leaflets, with the center leaflet featuring a longer stem. The plants grow in forest areas but also out in the open. Small, light-green flowers appear in June, and clusters of small, berrylike, pale-yellow fruits are ripe in September and hang on through the winter.
The common native poison ivy plants can be a nuisance to humans because of the serious skin irritations they cause, but they’re good ground cover that helps control erosion, is visually attractive and has considerable wildlife value. Included in the list of over 50 species of birds that eat the seeded fruits are sharp-tailed grouse, ring-necked pheasants, wild turkeys, black-capped chickadees, white-throated sparrows, yellow-rumped and Cape May warblers, and several of the woodpeckers. Black bears and rabbits are among the mammals that eat poison ivy leaves, stems and fruit.
It appears that only humans are susceptible to the toxic, oily compound that’s carried in the plant’s leaves, stems, roots, flowers and fruits. Sensitivity to poisoning can vary from person to person and can change during the course of a lifetime.
Jim Gilbert’s Nature Notes are heard on WCCO Radio Sundays at 7:15 a.m. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.