Toxicodendron Radicans - Distribution and Habitat

Distribution and Habitat

Poison ivy grows throughout much of North America, including the Canadian Maritime provinces, Quebec, Ontario, Manitoba, and all U.S. states east of the Rocky Mountains, as well as in the mountainous areas of Mexico up to around 1,500 m (4,900 ft) (caquistle or caxuistle is the Nahuatl term ). It is normally found in wooded areas, especially along edge areas . It also grows in exposed rocky areas and in open fields and disturbed areas.

It may grow as a forest understory plant, although it is only somewhat shade tolerant. The plant is extremely common in suburban and exurban areas of New England, the Mid-Atlantic, and southeastern United States. Similar species, poison oak, and Toxicodendron rydbergii are found in western North America. Poison ivy rarely grows at altitudes above 1,500 m (4,900 ft), although the altitude limit varies in different locations. The plants can grow as a shrub up to about 1.2 metres (3.9 ft) tall, as a groundcover 10–25 cm (3.9–9.8 in) high, or as a climbing vine on various supports. Older vines on substantial supports send out lateral branches that may be mistaken for tree limbs at first glance.

It grows in a wide variety of soil types, and soil pH from 6.0 (acidic) to 7.9 (moderately alkaline). It is not particularly sensitive to soil moisture, although it does not grow in desert or arid conditions. It can grow in areas subject to seasonal flooding or brackish water.

It is more common now than when Europeans first arrived in North America. The development of real estate adjacent to wild, undeveloped land has engendered "edge effects," enabling poison ivy to form vast, lush colonies in these areas. It is listed as a noxious weed in the U.S. states of Minnesota and Michigan, and the Canadian province of Ontario.

Poison ivy and its relatives are virtually unknown in Europe.