Living Sanibel: Poison Ivy
Although it would not look as good on the Chamber of Commerce’s tourist brochures, another appropriate name for Sanibel could well be “Poison Ivy Island.” This familiar, three leafed vine grows just about everywhere. The only place it does not seem to thrive is in the red mangrove forests, but a few steps back from the water’s edge, poison ivy can readily be found climbing the trunks of black mangroves.
There are numerous mnemonic rhymes that best describe the appearance of this highly toxic plant: “Leaves of three, let it be.” “Hairy vine, no friend of mine.” “Longer middle stem, stay away from them.” All of these refer to different identifying characteristics of this plant. Everyone is familiar with the three-leaf clusters of poison ivy. The hairy vine rhyme refers to the reddish hairs that can be found on most poison ivy plants and the longer middle stem is a way of telling the poison ivy plant from some similar looking vines such as the Virginia creeper, which is also quite common on the islands.
The biggest reason poison ivy is so prolific lies in its drupes. These grayish-white fruits are a favorite of cardinals, robins and warblers. More than 60 species of birds feed on poison ivy drupes and the seed hidden inside readily passes through their digestive system intact, creating a dynamic dispersal system that is unrivaled by any other vine. For this reason alone it is extremely unwise for anyone visiting the islands to stray far from the marked and cleared trails that are identified in the map section of this book.
Once off of these paths, poison ivy lies like an endless field of leafy land mines and the chances of getting brushed by one of these plants is almost a certainty. In the winter and fall, the three-cluster leaves will turn an attractive reddish orange, similar in color to an autumnal maple leaf.
The physical reaction to the oil, called urushiol, varies widely among individuals. Around 15 to 30 percent of people have no allergic reaction at all. The remaining 70 percent of people can develop everything from a mild rash that vanishes in a few days to severe dermatitis, requiring hospitalization. There are recorded cases of people going into anaphylactic shock and dying from contact with this extremely toxic plant. Eating poison ivy, which would be an incredibly stupid thing to do, can damage the digestive tract, the airways, lungs and kidneys of the victim.
Even the smoke from burning poison ivy has been known to make people extremely ill. People who are allergic to poison ivy should also avoid contact with mango trees and the outside skin of the mango fruit, as they are from the same family and produce a chemical compound similar to urushiol.
Once contact is made, a blistering rash soon develops. This is followed by oozing or weeping, wherein the toxins are excreted from the initial point of contact and weep downward, making a single incident last as long as four weeks. Remedies include the use of rubbing alcohol, Calamine lotion or Burow’s solution during the early stages of the dermatitis. Do not wash the rash with soap and water as this will only serve to spread the toxins, instead use rubbing alcohol. As the rash develops into blisters, oatmeal baths and baking soda solutions are recommended.
To relieve the itching, soaking or showering in the hottest water possible gives some relief. In severe cases, medical treatment is mandatory, with injections of corticosteroids being one of the best weapons against serious reactions. There are more than 350,000 reported cases annually of poison ivy dermatitis in the United States alone.
Worldwide, these cases number in the millions. Recent studies have shown that one of the many negative impacts of climate change, especially an increase in CO2 into the atmosphere, is that poison ivy will flourish in this environment. We are inadvertently building a perfect greenhouse for a toxic plant.
In its natural setting, poison ivy is an important plant. Its leaves provides a safe haven for butterflies to land on, since nothing will attack them when they are resting on a toxic surface. Birds love the drupes and left alone, it’s nothing more than a harmless vine. Look for poison ivy along the bike path that runs from West Gulf Drive to Bailey’s General Store along Tarpon Bay Road. There are stands of it on the west side of the bike path that are nothing short of amazing. Please just don’t fall over into one of them!
This is an excerpt from Living Sanibel – A Nature Guide to Sanibel & Captiva Islands by Charles Sobczak. The book is available at all the Island bookstores, Baileys, Jerry’s and your favorite online sites.