Poison ivy is a plant that I firmly believe every person in North America should be able to identify. It can be deadly if eaten, and deadlier if you burn it. It also makes a mighty fine rash if touched.
There is a common adage that most people know: "Leaves of three, let it be". This is a pretty good description if you're in the forest and know better than to dig around, but what if you are digging in your own garden? Strawberries and raspberries both have three leaves of very similar shape to poison ivy. One difference is that strawberry and raspberry leaves are jagged, whereas poison ivy leaves are "lobed", similar to oak leaves, but to a much lesser degree. There is no specific number of lobes, so you might only get one or two, or there could be too many to count at first glance. There are many good websites that teach you to identify poison ivy, and plants that look similar. This site also shows various bad rashes.
If you aren't sure if a plant is poison ivy and you really want to identify it, break off a piece (without touching it directly!!!) and spread the sap that comes out onto a white sheet of paper. After a few hours, the spot you wiped will turn dark. By the next day, it should be almost black.
I should point out that poison ivy is far more common than people think. Almost every walk in the woods will involve passing large patches of this ivy. I doubt most people recognize the rash that develops from poison ivy, and thus don't recognize the result. I've seen these rashes on my brothers (hands and up forearms, around ankles), my father (feet and shins), my boyfriend (forearms - got infected!) and ex-boyfriend (patches all over including belly, back and neck!), and this week, I managed to get it, too (fingers). If you ever touch poison ivy, it is the sap which sticks to you (and turns the aformentioned paper black) that makes the rash. Fortunately, an unbroken leaf should not harm you.
If you are ever unfortunate enough to get the sap on you, scrub it off as soon as you can. Even though you can't see it, pretend it is stuck on very hard, like pine sap, and use lots of soap. Also, remember everything you've touched as well as all the clothes and tools you might have brushed against it, and make sure they are all cleaned before you touch them again. I've heard that you have upwards of an hour to get it off without getting a rash, but that didn't work for me this time.
The rash takes about a day before you get the first blisters. They are very tiny, and at first look like little bumpy bites. Over the next couple days, these blisters multiply and new areas with blisters will appear. Each and every blister itches like a mosquito bite. These areas will turn red. If you get a very bad case, the little blisters will join up and become big blisters. They can, unfortunately, pop and make quite a mess. This is a very unpleasant rash and the best thing to do is learn what to look for and not get it in the first place. If you do get this rash, my best advice is to get a prescription for cortisone (corticosteroid) from the doctor to help you fight it off faster. Also, get medical tape instead of a bandaid to cover it, as tape will prevent rubbing. And last, deal with it. This can be weeks of painful itching.
So, how the heck did I get poison ivy if I know what it looks like? Well, it was hiding in the last place I expected it - my garden, amongst the strawberry, raspberry, and vine that might be virginia creeper. It's been growing in my neighbour's yard for years. He didn't know what it was, and didn't know why he got such painful rashes every year. It finally grew onto my side of the fence. He has asked me to get rid of his when I get rid of mine. This will be interesting.
I tried to kill it using RoundUp, an all-purpose plant killer that claims it gets absorbed and kills the root, and recommended all over the internet. I guess some business managed to make it "green" enough to get around the new pesticide law. All it has done so far is wrinkle up a few leaves, but the plant still looks healthy. I considered vinegar, but I want to kill more than just the leaves. Lately, I figured even if I manage to kill it, I still have to remove the dead husk. So now, the plan is to dig it out. I'll post more as events progress...