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What Time is it in Nature: Poison Ivy

January 3, 2014

If you’ve ever reacted to Poison Ivy (Toxicodendron radicans), you probably don’t like it very well. I know I don’t! However, Poison Ivy plays an important role in the environment and is a valuable part of Prairie Ridge’s natural landscape, especially during the winter. It’s time it gets its 15 minutes of fame on What Time is it in Nature!

Poison ivy

Poison Ivy

Almost everyone knows the phrase, “Leaves of three, let it be.” This is an important reminder of what to look for to determine whether a plant is Poison Ivy or some other species. Poison Ivy is a plant with leaves made up of leaflets in groups of three alternating down the stems.  The leaflets are broadly rounded where they attach to the plant and pointed at the other end.  However, there can be a lot of variation in shape, size, and color of the leaves, not to mention the plants themselves!  Poison ivy can be a thick, woody vine growing up a tree:

Poison ivy on tree

Poison Ivy on a dead tree – the “branches” of the tree are actually Poison Ivy!

It can also be a small plant lurking in a wooded area or grasses:

Poison Ivy in field

Poison Ivy in field

The leaflets can be shallowly lobed or toothed along the margins or smooth.  They also range in color from bright, pale green to deep, vivid green to olive during the spring and summer, and then they change colors in the fall to the season’s standard yellows, oranges, and reds.  In the winter when all the leaves have fallen from the plants, you might be left with woody vines growing up trees or stems sticking out of the ground.  Unfortunately, even without the leaves, Poison Ivy can cause nasty reactions if you touch it.  The compound that causes rashes, urushiol, is present in the sap of the plant, which means that even the vines and stems can cause a reaction.  You shouldn’t touch Poison Ivy, regardless of the time of year.

So now that we’ve covered what Poison Ivy looks like and why you should avoid it year-round, but let’s get back to the reasons why we should appreciate it!  Poison Ivy flowers in the summer and the fruits develop in the fall.  By the time winter comes around, most of the other plants with fruits have disappeared, but not Poison Ivy!  Birds do not react to urushiol the way people do and many of them love the berries, so Poison Ivy provides a very important source of food for a wide variety of birds.  You can often see dozens of birds flitting around in heavy stands of Poison Ivy, gorging on one of the best and most available foods left to them.  In fact, some of the best places to see birds in the early winter are near Poison Ivy plants!  If you like birds, you should definitely appreciate Poison Ivy because it draws them in.  Some mammals will eat Poison Ivy berries or leaves as well.  You might not want to go so far as to plant Poison Ivy in your yard to attract wildlife, but a walk through a Poison Ivy-rich forested area will often result in many wildlife sightings.

On recent days, we’ve seen Eastern Bluebirds, American Goldfinches, Red-bellied and Downy Woodpeckers, and several other birds feasting on Poison Ivy berries.  Wherever there are healthy stands of Poison Ivy growing up trees, you’ll likely see lots of birds munching on the white berries.  Next time you’re at Prairie Ridge, take a look at the Poison Ivy along the Forest Trail just beyond the trailer and on the tree outside the walkway to the Outdoor Classroom.  Once you see the abundant life that depends on it, you may never look at Poison Ivy the same way again!

[Web Editor’s note: you can see more photos and get more information about Poison Ivy on our Poison Ivy Flickr gallery.]

What Time is it in Nature is a weekly feature highlighting the current plants, animals, and other wildlife at the Musuem’s public outdoor facility, Prairie Ridge Ecostation.  Find out more about the natural happenings at Prairie Ridge at our What Time is it in Nature Archive!

(Photos by Chris Goforth)

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