POISON IVY is a woody shrub or vine with hairy-looking aerial roots. It grows to 10 feet or more, climbing high on trees, walls and fences or trailing along the ground. All parts of poison ivy, including the roots, are poisonous at all times of the year.
Poison ivy has:
three divided leaves,
center leaflet on a longer stalk,
white, waxy berries along the stem,
leaves alternate on the stem, and
erect shrub or climbing vine.
This descriptive information was extracted from Poison Ivy: How to Identify and Control, from the Conservation Commission of the State of Missouri.