Identification of Poison Ivy Vines

The Vine

• While poison ivy takes the form of ground cover or an erect, small shrub when a tree to climb is unavailable, it will grow upward as a vine on a tree trunk to heights as tall as 50 feet when a tree is near. The vine is woody, attaching itself tightly to the tree with its aerial rootlets. These rootlets keep the vine firmly secured to the tree so that the vine does not hang down limply or swing in the breeze. The rootlets appear hairy and grow outward from the vine, holding it close to the bark of the tree. The new growth is tan while old growth can be gray to brown. The thickness of poison ivy vines varies; some are quite thin while others may be stout and sturdy.

The Leaves

• The vast majority of poison ivy leaves are compound, with three leaflets attached to a central stem to form one leaf. Poison ivy foliage is variable from vine to vine, with the leaves capable of being glossy or dull, toothed or smooth-edged and with either a pointed end or a rounded one. The foliage is green, with some light green and others a darker shade. Their lengths differ, with some as short as 2 inches and others growing to 5 1/2 inches long. Poison ivy vines become highly ornamental in autumn; the leaves turn bright hues of red before falling off the vine, leaving it bare through the winter.

The Flowers and Fruits

• The flowers that develop during May through July on a poison ivy vine lack any ornamental significance, states the University of Connecticut Plant Database. The flowers are just 1/8 inch wide, emerging in clusters up to 3 inches wide, but are often hidden by the leaves. The flowers generate white berries as wide as 1/4 inch. They grow in clusters and are poisonous, but birds and other types of wildlife eat them with no ill effects, making the poison ivy vine a useful species in naturalized areas. Any berries undetected by birds sometimes stay on the vine into the winter.

Geography and Habitat

• Take into account where you live in Canada or the U.S./ when determining if a vine you discover is poison ivy. The distribution of poison ivy includes much of Ontario east to Nova Scotia, with its range extending southward to Florida and as far west as Texas. Its northern boundaries in its western range include states such as Minnesota and South Dakota. Poison ivy vines, when a tree is available to attach to, grow anywhere. They develop in open fields, swamplands, forests, roadsides, thickets and waste places.