I grew up on a beautiful 5-acre plot of land in Pennsylvania. A stone wall made from bluestone, a highly-prized sandstone that formed over 360 million years ago, separated our lawn and compost heap from the encroaching mixed forest. Like a mountain goat, I would climb onto our stone wall and run the length of it; sometimes I would jump into the leaves on the other side and play in the forest. One spring evening I came in to the house and began tearing at my skin. A red, blistery rash with bumpy yellow corpuscles emerged. My mom drenched me in pink calamine lotion. I had my first encounter with poison ivy.
Poison ivy (Toxicodendron radicans) is found in just about every state in the United States and it's estimated that up to 85 percent of people are sensitive to its allergenic oil urushiol, which was isolated by G.A. Hill at Wesleyan University back in 1934. This was the same allergen that had be identified from another related plant known as the Japanese lacquer tree (Toxicodendron vernicifluum), just 25 years earlier.
Most of us who spend a fair bit of time outdoors, hiking, gardening or weeding, likely have come across poison ivy. If we were lucky, we didn't unknowingly break any part of the plant, but if we were one of the unlucky ones—then I don't have to tell you that it's as if your skin is in living hell.
Poison ivy identification
The vesicant oil in T. radicans is found in its leaves, flowers, fruits, bark and roots. The leaves are pretty identifiable, if you know what to look for. First and foremost: they come in a group of three. The leaves are largely pointed, but I've also seen them rounded, so the three leaf-characteristic is the best marker. (I should note that Virginia creeper (Parthenocissus quinquefolia), which is a five-leaved climber and grows in similar habitat as T. radicans, is often mistaken for poison ivy, but is totally harmless).
Poison ivy's leaves can be both red and green. Oftentimes new leaves are red and leaves will turn red in the fall, but they're also often green, or mottled red and green. Shortly after the new leaves emerge, flower buds begin to show up on the stem. which give way to panicles of yellowish green flowers that bloom generally in late spring for around 2-3 weeks. Poison ivy can be both a shrubby and a vining plant, and is often seen climbing up trees or creeping along the ground. If you've removed it at any point—roots and all (something I'll get to later in the post)—only to find it in and around the same place next year—there's a reason for that.
Spread of poison ivy
Birds, particularly migratory species, love the white berries that show up in the fall. In fact, the berries are a particularly important source of fuel for the birds along their migratory routes. And even though consumption of the berries would be disastrous for humans, birds are immune to their toxins. If you've observed that poison ivy is often found around trees or by the sides of your house, then you're likely observing that because the tree or the house had served as a perfect perch for the birds, who had passed the seeds through their digestive tract, which in turn provided just the right conditions for the poison ivy seed to germinate. This is particularly the reason you may find poison ivy in a similar area year after year, even after removing it—roots and all.
Safe removal of poison ivy
Removing poison ivy is both an art and a science. If you feel comfortable enough removing it yourself then here are some steps you can follow:
Wear protective clothing. This may include a long shirt, pants and gloves. If you do get poison ivy oil on any of these, that the oil can remain in the clothing.
Wet the soil around the poison ivy area. Wait until after a heavy rainfall or use a hose to wet the entire area. This softens the soil and will allow you to uproot the poison ivy more easily.
Get old soil bags or thick plastic bags. You can place one bag down on the ground where you'll be kneeling to remove the vine. The other bags will be used to uproot the poison ivy. Be careful not to have the poison ivy touch any of your clothes, including your gloves, if possible. Use the bags as your block. Identify where the plant meets the soil and begin to pull up. Do this slowly until it starts to give. Carefully wrap it up into the bag without touching any of it. Stuff it into another bag so that it can be landfilled.
Wash clothes, shower. After you've tied up the plant into a trash bag, carefully remove your clothes and put them on a cold wash cycle. Then get in the shower and wash under cool water. Do not use any wash cloth, bath mitt, or shower gel or soaps. Water alone will dissolve the vesicant oil. Everything else will just spread it.
Survey area next morning. Head out to the area the next morning to see if you've removed all of the plant. If you haven't, then repeat steps 1-4 again.
Whatever you do, do not burn poison ivy. The resin in the poison ivy remains even when you burn it and can spread in the ash. If the urushiol-laden ash is then inhaled, it can cause serious lung irritation, which can result in hospitalization.
Additionally, if you feel ill-equipped to remove poison ivy yourself, then you can always call a removal service. Whatever the case, now you know how to identify poison ivy and stay safe gardening!