East Coast Poison Ivy Identification Guide
(skip intro- take me to the principles)
Clearly, prevention is the way to go, and prevention means poison ivy avoidance, and therefore poison ivy identification. There is plenty of information on the web and in print about dealing with poison ivy once you've touched it. If you are interested in what to wash with, how long before the oil won't wash off, preventative 'blockers', how long the toxic oils are active on garden tools, sketchy homeopathic treatments, etc, then I suggest you boot up google and have a look around. I'm interested in prevention. If you know what poison ivy looks like, and don't touch it, then all that other stuff doesn't matter. Or second best- if you know what it looks like, so you know that you did touch it, then you know to find yourself a cold stream/shower to rinse off before it causes a reaction. Finally, for all you lucky dogs who don't seem to be allergic to poison ivy- on behalf of all the people who are, please stop touching it, and then touching us. And yes, sometimes people who were never reactive suddenly come down with a massive case that sends them whimpering to the ER like the rest of us mere mortals.
Identification Principle Zero : Poison Ivy Doesn't Always Look the Same
This isn't really an 'identification principle'. It's a heads-up. Poison ivy can have leaf shapes that range from smooth and round, to narrow and sharp, with any number of lobes. Lobes may be sharp or rounded. Lobes may be symmetric or assymetric on the same leaf, or within the same cluster of leaves. Poison ivy leaves are often a reddish or brownish color when they are very young. They then turn green, and when they are dying or if it is fall, they turn yellow and red like other fall foliage. Poison ivy grows as low-lying ground cover, a woody-stemmed shrub that freestands to chest height, or a vine that covers walls and trees. It's leaves can be miniature to enormous. The leaves are generally no longer than, say, 9" along the long axis of the leaf, and more often than not are much smaller than that. However- the largest I've seen were almost 16", and perhaps they get bigger still. Identification Principle 1 : Poison Ivy Has Groups of Three Leaves |
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There. I said it. That is the basis of the venerable saying "Leaves of three, let it be." However, there are plenty of other plants who sport groups of three leaves, and to make matters worse, many plants who have groups of more than three leaves start with just three when they are young. Clearly, this is not a good identification principle. However, if you are in a part of the country where there is no risk of poison sumac (which unlike poison ivy and poison oak, has more than three in its leaf groups) then it's pretty failsafe. If you don't have the time or the flora-savvy to figure poison ivy out, just don't touch anything with three leaves. Easier said than done, I find.
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Identification Principle 2 : Poison Ivy Leaf Attachment
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Poison Ivy's three leaves are arranged so that there is one terminal leaf, and a pair of leaves further down the stem. The pair of leaves are exactly opposite each other, with leaves originating from the same point. In addition, the leaves in this pair butt right into the stem, unlike the terminal leaf which has its own little stem extension. Three-leaved plants where all three leaves have their own little stem extension are not poison ivy. Three-leaved plants where all the leaves originate in one spot, with no extension for the terminal leaf, are also not poison ivy. Very rarely, a poison ivy plant will appear to have extensions on its paired leaves, but it's very unusual.
Identification Principle 3 : Poison Ivy Does Not Have Finely Serrated Leaves.
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Poison ivy can have fine teeth, big lobes, small lobes, sharp or rounded lobes, all kinds of leaf shapes. However, poison ivy never has regular fine teeth, like the serrations on a bramble or a plethora of other 3-leaved forest plants. It is important to differentiate here: Yes, poison ivy can have tiny little teeth, but they are never regular, and around the entire leaf. This is a surprisingly effective principle in differentiating poison ivy from its harmless brethren.
Another important identification principle is hairy or otherwise prickly stems. If a plant has hair, bristles, spines, or thorns on its stem/branches, then it is not poison ivy. Please don't confuse this with bark. Poison ivy can have bark, or a woody textured surface to older branches on vines or freestanding growths, but it will not have the fine hair or bristles or thorns etc that you might see on a bramble or a variety of other forest plants. |
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