Wednesday, July 1, 2015

What's Your Poison?

When we started clearing the woods of garlic mustard this May, it didn't take long before I began to spot small shrubs that looked like poison ivy, but may or may not have been. I have long been aware of the morphological nature of poison ivy, Toxicodendron radicans. In the blazing sunshine of New York beach dunes it shows as a glorious shining-leaf shrub thicket or in the dry woods of Long Island it appears as a vining, often shiny but not always, plant growing up trees or just as often a three-leafed low shrub colony at the edges of woods and fields. In the deep, wet woods of Maine it often took the appearance of fresh, pale greenery growing low to the ground. 

Rex always said poison ivy was not growing on the property, but I knew it grew across the road in the sunshine, in front of and under the Alders. Because my possible sightings took place in dappled sunlight or on slopes recently made sunny by fallen oaks along with what I consider a cohabitant, wild grapes, I began mentally bookmarking each specimen as a potential rash. I posted on FB and the results were nearly fifty fifty split between poison and not poison, yet no one could provide a possible alternative to poison ivy.

Leaves of three, let in be -so the saying goes.

But what of this? Sometimes PI looks just like trees.

Another clue is the short branches on side leaves, long on front leaf. 

Surely that is poison ivy. Alternate veining on the leaves.

You say, no way -not this one? But see here

Mitten-shaped leaves, leaves of three, alternate veining? 

Reddened stems, alternate veins, short side stems, three leaflets, perfect habitat?

If this isn't poison ivy, then what is it?

Turns out that's not poison ivy growing about our dappled clearings. This one clue deciphered it: opposite branching on our plants. Poison ivy has alternate branching. How did I figure it out?

While Betsy and I were clearing the area around the mailbox at the road, I saw a small tree, but definitely a tree, that had leaves just like our little specimens around the yard. I googled tree that looks like poison ivy (why didn't I think of that first?). It's an Ash Maple, Acer negundo, also known as Boxelder. After two weeks of surveying, each had grown enough to reveal their true identity. Then I found this definitive guide that goes beyond all the hooey about leaves of three you'll find on the Internet. Keep the pdf on your phone when your hiking and all your identification problems will be solved.


  1. Very helpful guide. After years of not getting it, about 10 years ago I got really sensitive to it and now I am vigilent! Thanks.


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