The first guideline is Leaves three, let it be! That's a good place to start, but there are lots of plants with three leaves. My goal here is to present some pictures of poison ivy and highlight what I think are some key features that I use to identify and differentiate poison ivy from similar plants. Hopefully some familiarity with this plant will make it easy to instantly spot it in the wild or in the garden.
Larger size copies of the images can be viewed at my Picasa web album.
This first image shows the typical "three leaves" and highlights the notches in the leaf margins.
Young leaves and more notches. The youngest leaves have not developed any notches yet.
This picture taken in June shows the berries just starting to develop as well as the domed shape sometimes seen on larger leaves. The individual leaves can sometimes grow to be as big as my hand under favorable conditions.
In this picture you can see the beginnings of the adventitious roots that help the vines to cling to the bark. These can cover older vines giving them a downright hairy appearance.
Not Poison Ivy
This is Box Elder which can look a lot like poison ivy. Older leaves will be clustered as five or seven whereas Poison Ivy is virtually always three. It also has shoots and branches vs. vines.
Raspberries may have three leaves but is easily differentiated from Poison Ivy by the sawtooth leaf margins, thorny canes and raspberries.
Honeysuckle won't likely be confused with Poison Ivy, but it looked pretty in full bloom so I took pictures of it as well.
