Poison Ivy Timeline. Poison ivy, poison oak, and poison sumac are all plants that can cause a temporary, irritating rash when they come in contact with your skin. Brushing against a poison ivy plant can cause a red, itchy rash with swelling, bumps and blisters.
Poison ivy is a toxic plant that's commonly found throughout most of the continental United States. In later stages, these vesicles are filled with fluid. I always keep a bar in the medicine cabinet.
Thankfully, there's a method for controlling the madness.
Poison ivy, poison oak, and poison sumac are plants that contain an irritating, oily sap called urushiol.
When they ripen (in late summer to early fall), they turn from a pale green to a whitish color. Poison sumac also has a curious white berry. Then, of course, it's time to get rid of poison.