Leaflets of Three, Leave Them Be

And of who else might we be speaking of but… none other than the much maligned poison ivy vine. Poison ivy (Toxicodendron radicans) is in the sumac (cashew) family Anacardiaceae. Other notable South Eastern relatives of poison ivy include Eastern poison oak (T.pubescens), poison sumac (T. vernix), winged sumac (Rhus copallina), and one of our least favorite plants the non native invasive species Brazilian pepper (Schinus terebinthifolius). I have not found poison sumac very prevalent in our area and poison oak seems to be restricted more to northern Florida by all accounts. If you have come across either in our area, I would love to know. (note that all of the plants mentioned above may cause a skin rash if you come in contact with them, depending on your sensitivities)

I think the old saying went something like “leaves of three, leave them be” where actually it should say “leaflets of three”. Instead of three leaves,  you are actually looking at one leaf with three leaflets. But if it helps you to remember, we’ll leave that be as well. Poison ivy contains an irritating oil called urushiol. Contact with this oil that comes from all parts of the poison ivy plant may cause dermatitis (sometimes extreme) in some people. The American Academy of Dermatology recommends washing any exposed areas with soap and water as soon as possible after contact to remove the oil as well as promptly laundering any contaminated clothing. Over the counter medications to relieve the itching and patience are the only treatment for the rash that may last more than a couple of weeks. Of course, see a doctor for severe exposures.

Avoiding contact with poison ivy is your first defense. There are otc products available to apply to exposed skin to prevent contact with the urushiol oil. Be mindful that you can also come in contact with the oils of poison ivy from your clothing or pets exposed to the plant. Take special precautions when mowing or weed eating poison ivy as the oil can can be sprayed everywhere from the cutting action. Burning poison ivy may volatize the oils allowing them to be inhaled, not good.

Knowing your enemy: Poison ivy is a deciduous vine (meaning they lose their leaves in the winter) whose alternate leaves have three unlobed or slightly lobed leaflets each. Very pretty clusters of fragrant white flowers (very attractive to bees) are followed by white/tannish drupes in the spring around May. In the fall, the leaves turn bright red before falling from the plant. When the plants are leafless the stems, attached to trees or other surfaces, are still easily recognized by their dense aerial  roots that gives them a hairy appearance. Their hairy appearance readily distinguishes them from grape vines with no aerial roots or Virginia creeper vines that have sparse rootlets with five little pads at the end.

leaf of poison ivy with three leaflets (on left) by the similar non toxic Virginia creeper (Parthenocissus quinquefolia) with five leaflets

woody stems of poison ivy covered in aerial roots

Nothing evolves to be just  a menace or nuisance so, what value is there in poison ivy you might ask? Well, countless numbers of songbirds are known to dine on the berries through out the plants range. Some of those sighted in Back Woods know to partake in a poison ivy berry or two include: Gray Catbird, Northern Flicker, Eastern Phoebe, Brown Thrasher, Tufted Titmouse, Cedar Waxwing, Carolina Wren, and Woodpeckers (Downy, Pileated, and Red-bellied). Additionally, bees love the flowers and deer browse on the foliage. Yay, poison ivy!

There are many web pages dedicated to poison ivy just a search engine away. One comes complete with slightly gruesome collection of photos called the “Skin Rash Hall of Fame”, ewww! You will find there great incentive to know your poison ivy and take the right steps to avoid exposure. As someone I love always reminds me, everything bites…so, get outside!!