Itchy Scratchy

Poison Ivy climbing a Hornbeam or Musclewood Tree in Florida

This is a public service message brought to you by a representative of the sensitive skin club. Me. It's that time of year again when the birds and bugs are active and the new summer flowers are blooming on the roadsides. It's also the time that the skeeters are biting, the ticks and chiggers are lurking in the grass, and the Poison Ivy is sprouting. And when I go out in pursuit of nature adventures and good photos, I keep finding myself face to face (or ankle to leaf) with the whole lot of them. Today I would like to familiarize you with Eastern Poison Ivy (Toxicodendron radicans). Perhaps some other day I will have something nice to share about ticks and chiggers. I have a hard time seeing any redeeming points in those pests, so I have (so far) no photos. But Poison Ivy, on the other hand, is actually a pretty plant. And it is also bigger than a pinhead (unlike chiggers and ticks), so I have lots of photos to share. But I digress.

This all came to me a month or so ago when I was traveling in Northern California at the Elkhorn Slough National Estuarine Research Reserve and came across a huge patch of Pacific Poison Oak. I'm not so familiar with Poison Oak (Toxicodendron diversilobum), but I was able to recognize it because of some helpful signage, and therefore kept my parents and myself from accidentally brushing against it. It did look somewhat similar to the good ol' itchy stuff from back home, but as a lush and bushy plant, it had a different habit and I might have accidentally blundered into it without the signs.

When I got back home it was time to lead school groups on trail walks at the nature center, and the beginning of Poison Ivy season, and I always try to help the kids learn to identify the plant so they can enjoy the outdoors without the itch. My experience in California got me thinking that I wasn't sure I knew the difference between Poison Oak and Poison Ivy. I have often heard people equate the two, so I did some research and learned some interesting facts about these plants. I have never come across Poison Sumac which also grows in the South, though I am familiar with other types of Sumac.

Poison Ivy is not actually ivy, and Poison Oak is not an oak. Both plants, and Poison Sumac are all in the same plant family, Anacardiaceae--the Sumac or Cashew family. The family also includes Mangoes and now Pistachios. These plants are not poisonous in the sense that they will kill you (unless you have a severe allergic reaction). But they have sap that contains Urushiol, a compound that causes (sometimes severe) contact dermatitis. I recently learned that the people who process cashew nuts can get a similar reaction from handling the sap and so it is important to buy cashews from ethical sellers who protect the health of their workers.

All parts of a Poison Ivy plant can cause the skin reaction. The leaves, the berries, the vine, and even the dead leaves and vines. Urushiol can become airborn if the plants are burned, or ground fine with a mower, so care must be taken when handling the plants at all times. I believe that Poison Oak and Poison Sumac are similar, but I am not sure because I don't have direct experience with either one. But as I read more I learned that though Eastern Poison Oak does occur in the Southeast, it is not as common and looks a lot like Poison Ivy and it is hard to distinguish between the two. Poison Sumac is also present in the Southeast, though it is even less common, and this may explain why I don't know those plants well. Poison Ivy, on the other hand, is widespread across the eastern half of the US. Pacific Poison Oak is extremely common along the entire West Coast.

Most people are allergic to these plants, though not all. About 85% of people react. The other 15% can consider themselves fortunate, but they still need to be careful because the oils from the plants can be tracked into the house on shoes, tools, clothing and even pets, and when that happens, the reactive people in the household will become very angry. Animals do not seem to be bothered by the irritating oils, maybe because of fur or feathers, or they're just born lucky.

If you do come in contact with one of the itch-causing plants, wash and scrub immediately and vigorously with cold, soapy water, or with special soap such as Technu. Simple handwashing won't work. And warm or hot water is not good because it opens your pores and lets the oils sink in deeper. If you can find some Jewelweed, which conveniently grows in the same habitat as Poison Ivy, it is supposed to help. If you get the rash, I pity you, but calamine lotion does help. But the best thing is to just avoid it. I have had Poison Ivy rashes twice. Once when I didn't know the plant and got into it in my Florida yard. It took 3 weeks for the rash to stop itching and oozing. The other time I just got careless and brushed my cheek against a vine, even though I had been told to watch out. Another 3 weeks of itching and oozing later, and I was a crusader for Poison Ivy avoidance.

If you have Poison Ivy in your yard, my experience is that you can remove it if you are cautious. Use disposable gloves and clean your cutting and digging tools very carefully and you should be ok. Be careful not to let it get on your clothes or you can spread it to other items in the washing machine. As I mentioned, if you mow or burn, be careful not to breath the airborn sap, or you may find yourself in the hospital or taking steroids.

Jewelweed (Impatiens capensis) is a traditional remedy for Poison Ivy rash

So how do you avoid this stuff? Get to know it and stay away from it! And wear closed toed shoes and long pants in the woods. That's how you keep the ticks and chiggers away, too, so I'm always ready.

I don't know anything about Poison Sumac, so I won't try to help you with ID. You're on your own there. Photos I find online resemble other Sumacs I've seen. And I'm not an expert with Poison Oak, either, which appears to be a shape shifter that can grow into a big bush that looks like an oak tree. Descriptions say they can have 3 or 6 or 9 leaves. Here is my one photo from California. You can see that this one does resemble Poison Ivy.

Pacific Poison Oak (Toxicodendron diversilobum)

But for Poison Ivy remember these:

"Leaves of three, leave it be" or "Leaves of three, don't touch me"

Poison Ivy (Toxicodendron radicans), 3 leaflets. I think that on young plants, the outer two leaves look like mittens.

Poison Ivy leaves grow with three leaflets on a stem. The edges can be smooth, or lobed, but the leaflets will grow in clusters of three. Often the young leaves have a shiny, waxy look. I think the young outer leaflets resemble mittens.

Poison Ivy can be a trailing vine, a climbing vine or a small shrub. It will not have thorns. If it has thorns, you may get poked, but you're safe from Poison Ivy! (Unless they're growing on the same tree, which happens a lot). Many plants are mistaken for Poison Ivy. Here are a few.

This one looks like Poison Ivy but it is a Boxelder sapling. Look for toothed leaf edge, and opposite pairs of leaf stems from the main stalk.

Not Poison Ivy. This is a Blackberry. The leaves are toothed and the stem has small thorns.

Also not Poison Ivy. This plant is in the Legume (pea) family. It has 3 leaves, but they are a more teardrop shape and the leaves are hairy.

This is Virginia Creeper and is often mistaken for Poison Ivy, but it is not. Notice the 5 leaflets rather than 3.

Oak Leaves. Not Poison Ivy or Poison Oak

Poison Ivy plants sprout on the ground and the vine grows, often climbing a tree. An older vine can be deceptive because it can grow branches and the leaves can be huge. But they will still adhere to the "leaves of three" rule. If you have climbing vine a you can use the next mnemonic,

"Hairy is Scary"

Poison Ivy vines have root hairs to attach to the tree trunk and the older vines can almost look like a furry beast climbing a tree. In the winter when the vines have dropped their leaves (they are deciduous), the hairy vine can be your only clue that there is Poison Ivy nearby. Don't hug trees with hairy vines. And speaking of deciduous vines, be cautious when collecting spear-shaped red and orange leaves if you don't know what tree they came from. They could be Poison Ivy.

Big and hairy vine. To me it looks like a monkey tail.

Poison Ivy vine that climbed a Tulip Poplar and grew branches. Most of the branches you see are the Poison Ivy. 

Poison Ivy in fall colors. It is beautiful!

So if these plants are to be avoided at all cost, why don't we just eradicate them? The kids always ask me that. But I tell them to consider this: the leaves are pretty, lush and green. In the fall they are a gorgeous red, orange and yellow. They provide cool shade and oxygen in the forest and contribute to the biomass. They give shelter to birds, insects and squirrels, and their berries are food. Poison Ivy is just another part of the forest. Just because something annoys people doesn't mean that it shouldn't exist. We just need to find a way to live around our annoying neighbors because they are the spice of life.

Poison Ivy berries (they are white--this is an identification tool) provide important food for wildlife

Yellow-bellied Sapsucker climbing a tree with hairy Poison Ivy vines

Question Mark Butterfly amid the Poison Ivy leaflets