Poison ivy is a green plant that has a shiny reddish tinge in the spring and always has three leaflets. The leaves are usually anywhere from 2 to 6 inches long and can have smooth or toothed edges.
The form of the leaves may vary even on the same plant, and may make identification difficult. Poison ivy grows in both shaded and sunny areas. The plant can climb trees and fences and is also commonly found along roadways or paths. Although reactions vary, many people develop itching and swelling 24 to 48 hours after coming into contact with poison ivy.