Poison sumac is a shrub or small tree that grows in water-oversaturated soil, primarily in swamps and marshes. All parts of the poison sumac plant are toxic to the touch, causing a severe rash, and the smoke from burning poison sumac can be fatal if inhaled. Although it has the same toxicity mechanism as poison ivy and poison oak, relying on a chemical called urushiol, it is part of the cashew family and not botanically related to poison ivy and poison oak. There is a number of fairly easy ways to identify poison sumac so that contact with it can be avoided.
The simplest way to identify poison sumac is by the kind of soil it grows in. Although other types of sumac bear a resemblance to the poison sumac plant, poison sumac grows only in wet soil, and it’s rare to find a poison sumac plant growing next to a different type of sumac.
Another easy way to identify poison symac is by its distinctive leaves. The poison sumac has a compound leaf usually consisting of seven subleaves. each subleaf is oval in shape and pointy at the tip, with a smooth-looking underside. Early in the growing season, which occurs in late spring, the leaves typically point upward from the branch. Poison sumac is deciduous, which means that in fall the leaves turn a deep red and eventually fall off.
Even in colder weather, when the poison sumac plant has no leaves, it can be identified by its berries, which continue to hang from the branch after it has been denuded. The berries occur in large clusters but are themselves tiny, averaging less than a fifth of an inch (0.5 centimeters) in diameter. They are white. Although some birds eat them, they are also toxic to human touch. In late fall and in winter the berries may fall off and be found on the ground.
Poison sumac bark is grayish in color and moderately rough. The largest poison sumac trees grow to about 20 feet (7 meters) tall. Like the leaves and berries, the bark contains urushiol and should not be touched.
Poison sumac has been found only in parts of the eastern United States and in Canada, so it is unlikely to be a concern to people in other countries. The best way to avoid contact with poison sumac is to be careful when travelling through boggy areas.
