Toxicodendron radicans (poison vine, markweed, poison creeper, three-leaved ivy, picry, mercury)

description: deciduous vine

place of origin: eastern North America

urban habitat: commonly found climbing up telephone poles, buildings, chain-link fences, tree trunks, along unmowed highway banks and railroad tracks; thrives under a variety of conditions, moist soils and dry, sandy sites, in full sun or shade.

ecological function: food and cover for wildlife, erosion control; tolerant of salt and compacted soil.

history: Captain John Smith was the first European to describe Toxicodendron radicans in 1624, noting that touching the plant caused “rednesse, itching, and lastly blisters.” Poison Ivy has been used medicinally and was used by the Shakers to treat chronic paralysis, rheumatism, skin diseases, and bladder paralysis. Several Native American tribes used the leaves as treatment for boils and other skin aliments and the Navajo used a compound of the plant to make poison arrows. All parts of the plant can cause allergic dermatitis, in winter or summer, in 60-80% of people. The leaves are rich in tannin and can be used to produce a brown dye or ink.