Introduction
Poison ivy (Rhus radicans) can be found in nearly any part of Michigan. It is known by several different names, such as three-leaved ivy, poison creeper, climbing sumac and poison oak. Its usual growth habit is as a slender vine running along the ground, or growing on shrubs and trees. The vines are capable of growing to several inches in diameter over a period of years. Poison ivy has three leaflets occurring alternately along the stem. Leaflets are usually smooth, but may be either a dull or glossy green. Leaf margins (edges) can be smooth, toothed, and/or lobed. Leaves on the same vine often have a number of color and leaf margin combinations. It is possible however, that all leaves on a vine will have the same general character. In general, however, there are no distinguishing characteristics to warn an unsuspecting individual that a vine is poison ivy.
Poison oak and poison ivy can be dangerous plants, but they also have positive characteristics. They provide nourishment to a wide variety of animals including many birds, rabbits, deer and bears. They are useful for soil stabilization and erosion control, particularly in areas that have been disturbed. They also make effective natural boundaries. Native to the United States and flourishing in the Northwest, these plants will be with us for the foreseeable future. Consider leaving poison oak and ivy alone if it is not a threat to people. Poison oak and ivy are only a danger if people come in contact with the plant and its chemical oil, urushiol. This chemical can cause swelling and blisters when it bonds with human skin. Many, but not all people are susceptible. Some people may not be affected the first or second times they are exposed, but on subsequent exposures have strong allergic reactions.....
