How to Identify Poison Ivy



Well kids, it's that time of year again! Mosquitoes and Poison Ivy.  Yes, I know, these guys are here in Texas year around.  For us in the southern U.S. states, it's full blown summer, kids are out of school and its time to get out of the house and enjoy the weather before it becomes unbearable.

So while out and about you must know your enemy.  Can you identify poison ivy?  It can be tricky for sure.  If I learned anything from my Plant Taxonomy course it's you never pick a plant your professor tells you to pick up.  Thanks, Dr. Williams.  The second thing is that plants can look very different based on the amount of sunlight, soil, season and geographic location.  I will be using examples I have come across here in Texas, most of these characters will be similar to other regions throughout.

So here we go:

First, should you even be worried?

From the USDA, if you live in these states, then yes.


But if you are in a white state, you don't get off that easy.  There is still poison oak...it's in all states and in Canada.

Alright, you may remember the little rhyme "Leaves of three, let them be".  It's not bad advice at all really, it can help you eliminate many of the plants that are often mistaken for poison ivy.  But let's dig a little deeper and really pin down the identification.  Otherwise, you won't be able to go outside for fear of poison ivy, because there are a lot of harmless three leaf plants

Generally, the two outer leaves of poison ivy will have a notched side and smooth side.  The notched side will be facing outward while the smooth side will be facing the middle leaf.  Sometimes the notch is very prominent, and sometimes it is hardly visible.  The trick though is that difference in leaf sides.  


The middle leaf....well, it's highly variable.  Sometimes it's smooth on both sides, sometimes is has a notch on both sides.  So there ya go.



Two plants I often see mistaken for poison ivy are young Virgina Creeper and young Dewberry plants.  Notice that Virgina Creeper has too many leaves and Dewberry has too many notches, or teeth along its leaf edge.  Dewberry also has spine or thorns on its stem.  Poison Ivy will not have thorns.

Virginia Creeper
Dewberry


Poison ivy can also be in a vine form.  It's like a Pokemon.  Not only do you need to look on the forest floor, but also climbing up a tree.  Sometimes you will see the leaves, sometimes not.  I would say look for fuzzy looking vines...but even then it may not be poison ivy, so just error on the side of caution and leave it alone.

Ok quiz time:

Can you spot the poison ivy?

Find the Poison Ivy

Solution 1

Well done.  One more!

Where is the Poison Ivy?

It's everywhere!

Is this poison ivy?

Nope!

A few more features to look out for, but may not be as definitive as the leaf shape.

  • You may also see red coloration on the stem 
  • Leave are not evergreen and will turn red/yellow in the fall
  • Young leaves can be red and hard to identify
  • Mature leaves can be very large and rounded

I've included a few more links that get into the details of identification.  But as long as you take your time in the forest and practice identification, you will pick up on the small differences and variations of this plant.  Happy Trails!


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