Ontario Wildflowers website

Poison Ivy & Poison Sumac Group

To see all  Poison Ivy & Poison Sumac  in order by Common Name     START HERE
  • Poison Ivy (Toxicodendron rydbergii)
  • Poison Ivy (Toxicodendron radicans)
See also:

Poison Ivy is a poisonous-to-the-touch plant that grows in open woods, rocky areas, and fields. All parts are poisonous.

The oils within the plant cause an allergic reaction in many (but not all) people, that can be quite serious. This allergic reaction manifests itself as a rash, that may show up on parts of the body that did not contact the plant at all. Sometimes people who contact Poison Ivy have a body-wide reaction, and are seriously ill for more than a week.

For information about cures for Poison Ivy rash, please see the Poison Ivy Cures page.

The oils from the plant can are easily transferred to others. For example, a dog may romp through a patch of it, and then transfer the oils to people who pet the dog. It is said that the oils remain virulent throughout the winter, although poisonings from it then are probably very rare. This is tricky, since at that time the plant has no leaves; it just looks like an innocent small branch sticking up out of the ground.

Obviously, ingesting poison ivy is not advisable, although some people claim that this builds immunity to the oils.

Burning Poison Ivy is not advisable either, as the oils go up with the smoke. If someone was to breath in the oil-laden smoke, then they can actually get poisoned inside their lungs!


The classic way to identify Poison Ivy is the 'three leaves' configuration. In other words, if a plant has 3 leaves in a compound leaf configuration, assume it is Poison Ivy until you know otherwise.

Size and Shape: A small shrub (meaning that the stem persists through the winter) or vine. In the northern part of its range (north of the Great Lakes) it remains on the ground. Further south it climbs trees as a vine, its own branches mimicking the tree's branches.
Leaves: Three leaves in a compound leaf arrangement. Highly variable. Hairless or slightly hairy. Glossy or dull. Toothed or smooth-edged or lobed. The end leaflet is pointed, and has a longer stalk than the other two leaflets.
Stems: Woody, persistent through the winter. Climbing stems are covered with short rootlets and dark fibers. Grows as a low shrub (up to about 1 foot tall) or a vine climbing the sides of trees.
Berries: Small, white, hard. Sometimes persistent through the winter. Birds eat them. In drooping clusters. Not edible.
Habitat: Open woods, rocky areas, and fields.
Range: S. Canada and south to Texas and Florida.

There are several Poison Ivy non-poisonous look-alikes (see the Poison Ivy Look-alikes page).


Poison Ivy (Toxicodendron rydbergii)
Poison Ivy
(Toxicodendron rydbergii)
To see all  Poison Ivy & Poison Sumac  in order by Common Name     START HERE