Poison Ivy (Toxicodendron radicans)

DESCRIPTION: Poison ivy can occur as a vine--either climbing the trunks of tree species or growing along the ground--or supporting itself as an upright shrub. Its glossy compound leaves are variable; their array of three leaflets is often toothed or lobed, although the borders of the leaflets can also be unbroken. The arrangement of the leaflets is indicative of poison ivy: the middle leaflet extends from a long petiole, the base of which is flanked by the lateral leaflets. The foliage often hides a woody stem and flowers. The flowers bloom from the leafless lateral branches in clusters of up to 25 flowers, and give way to yellowish-white berries in the fall. Aerial roots are usually associated with poison ivy. The multiple roots cling to trees summer and winter, making identification of the dormant plant possible.

DISTRIBUTION AND HABITAT: Found mainly in the eastern half of the United States, poison ivy is common in open woodlands, preferring trees in disturbed habitats. The plant grows unsupported in open sites as well. It also grows well in river bottom forests.

LIFE HISTORY AND EFFECTS OF INVASION: Poison ivy blooms from early to mid-summer, its bunches of small, off-white flowers opening under the vine's dense blanket of foliage sometime between May and July. In midsummer, the flowers give way to small clusters of berries.

Poison ivy is generally not harmful to other native flora. Oils from the leaves and stems are, however, irritating to humans. Smoke from burning poison ivy is also dangerous. Because this species prefers disturbed areas, it is commonly found in many human altered environments, including trails, parks, yards, and recreation areas.

CONTROL METHODS
Mechanical Methods: Uprooting individual plants is a common method of control. This is most safely done in late fall, either before or after the leaves have fallen. Gloves and protective clothing are advised to prevent exposure to the plant's oils. When pulling, remove the entire root to avoid resprouting. Once dry, the plants should be disposed of in the trash, along with the gloves. Plants should never be disposed of by composting or burning; the former may result in resprouting, the latter in the release of irritating fumes. Pulling must be repeated for several years in order to deplete the seed bank.

Chemical Methods: Poison ivy can be controlled in late spring or early summer using herbicides. Glyphosate or 2,4-D can be applied at label-recommended rates to the foliage with a sponge or sprayer. This procedure also must be repeated for several years to deplete the seed bank.

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