Poison ivy is a plant.
The plant can take the form of a vine or shrub.
The leaves are compound and arranged alternately (not across from each other) on the stem. There are three leaflets per leaf with the central leaflet on a longer stalk than the other two leaflets.
The leaves may appear to be shiny or oily.
The leaf edges may or may not have a few teeth, but they are never saw-toothed or divided into many scallops.
Leaves turn red, yellow or orange in the fall.
New leaves may also be red or shades of red.
The vine form can be about 60 feet long.
The shrub form may be two to four feet tall.
The plant can also be very short.
Poison ivy grows in every Illinois county.
It lives in fields, woods, along streams and lakes and in disturbed areas.
It makes its own food.
This species blooms from May through July.
Flowers are green-white to white.
Pollinated flowers produce small, white, spherical fruit.
Poison ivy can also spread through vegetative (asexual) reproduction.
White-tailed deer (Odocoileus virginianus) eat the plants.
Birds and other animals eat the fruits and disperse the seeds in their wastes.
- A chemical, urushiol, in the plant’s sap may cause irritation, a rash and/or swelling in people.
- All parts of the plant contain urushiol and damaging them may cause the sap to come in contact with people’s skin, but the sap may also be transferred to people indirectly through pet fur or other means. If poison ivy plants are burned, this chemical can be transferred through the air, too. Breathing urushiol is dangerous. Learning to identify poison ivy is key to avoiding contact with it.
- There are four key traits to identifying poison ivy: compound leaves with three leaflets; each leaf has its own connection to the main stem; alternate leaf arrangement along the stem; no thorns.
- “Leaves of three, let it be” is a common saying to help you remember what poison ivy’s leaves are like. There are other plants with three leaflets, though, so also look for hairy vines (aerial roots along the vine appear hairlike) and white, spherical fruits.