Identifying and Eradicating Poison Ivy
If we lived in a just and perfect world, poison ivy would have 10-inch thorns and a noxious smell. Alarms would sound as we approached it—or better yet, creepy organ music would fill the air.
Unfortunately, in the real world both Toxicodendron radicans, the common climbing variety, and Toxicodendron rydbergii, the western shrub species, are attractive plants. In fact, if you didn't know Toxicodendron was poison ivy, you might be tempted to snip off bits of it for your fall floral arrangements. (It's at its prettiest in autumn.)
Poison ivy is not only attractive; it's also quite prolific. Once it takes root on your property, it can self-seed rapidly and develop into a potentially dangerous nuisance.
Poison Ivy Through the SeasonsClick thumbnail to view full-size
How to Identify Poison Ivy
Poison ivy grows on every continent in the world. And it's present in every U.S. state, excluding Alaska and Hawaii.
You'll often find it along streams and rivers. It likes the coast, too. Sometimes, you'll even see it at the beach.
As you can tell from the photos to your right, poison ivy looks different depending upon the season. In spring, its new growth has a rosy hue, and plants may develop small green buds that eventually bloom into tiny, nondescript white flowers. After a time, these turn into greenish-yellow berries.
In summer, poison ivy leaves are bright green. In autumn, they turn red. In winter, when the plant becomes dormant, its roots are rust-colored. Like every other part of the plant, they can cause a rash, too.
The saying, "Leaves of 3? Let it be," holds true. But keep in mind that many plants have leaves that grow in clusters of threes.
One of the best ways to distinguish poison ivy from similar looking plants is by the black spots that appear on its stems where its leaves have fallen or been torn away. These spots indicate the presence of urushiol, the oil in poison ivy that causes contact dermatitis.
Poison Ivy Look-Alikes
Poison ivy is easily confused with Virginia creeper (Parthenocissus quinquefolia), a harmless fast-growing vine with five, not three, leaves. It produces purplish fruit in the fall.
Sometimes poison ivy is mistaken for a tree, the benign box elder (Acer negundo) which, like the poison ivy vine, often graces the banks of woodland streams throughout North America.
The Unpleasant Power of Urushiol
Bees like poison ivy blossoms. And in October, many birds will gobble down its pea-sized berries. Hungry deer and goats suffer no ill effects from eating it, and dogs and cats can frolic in it without harm.
Only humans seem to have an adverse reaction to urushiol. In fact, most of us will develop an uncomfortable rash when exposed to only a small amount of it. Even people who don't currently react to poison ivy often develop sensitivity to urushiol over time.
You don't have to touch poison ivy in order to be exposed either. If your pets have been in contact with it and have urushiol on their fur, you can pick it up from them. You can also get urushiol from tools that have been used to cut poison ivy. And if you mow poison ivy, urushiol can "spray" into the air and get you that way!
Because urushiol is so ubiquitous and caustic, it's important that gardeners take precautions before attempting to remove poison ivy from their landscape.
When tackling a poison ivy problem, dress for the occasion. Go for full coverage: socks and shoes, long pants, long-sleeved shirt, and disposable rubber gloves.
If your clothes are also disposable, even better. If not, wash them as soon as you're done, being sure to handle them carefully. (You don't want any urushiol that may have gotten onto them to come off onto your skin.) Wipe down your shoes, as well as any tools that you used, with rubbing alcohol.
Clean yourself, too. Take a long, cold shower to remove any oil from your skin. Avoid hot water. It will open your pores, allowing them to absorb the oil—and guaranteeing that you get a great big rash.
Wiping yourself down with rubbing alcohol is another effective way to remove urushiol, so long as you do so promptly. The cleansing agent Tecnu, which is specifically made to rid skin of poison ivy oil, also works.
Aggressive cases of contact dermatitis are dangerous due to the risk of infection. If your symptoms are severe, visit a healthcare professional. Likewise, if cuts or open wounds on your body come into contact with urioshol, causing you to develop a rash, go to the doctor immediately.
Eco-Friendly Options for Eradicating Poison Ivy
Manually removing poison ivy can be an itchy, labor-intensive proposition. The garbage bag method below eliminates the itchy part, but its hard work. The plastic sheet strategy is a passive method of control that, after the initial labor, requires little or no work.
The Garbage Bag Method
The garbage bag method works well on small poison ivy shrubs and vines. If you're dealing with well-established plants, you may have to repeat this method several times:
- Open the garbage bag and put it over the poison ivy.
- Using a long-handled shovel, begin to dig up the plant.
- Once the soil is loosened, grab the poison ivy through the garbage bag, pull it free, and maneuver it into the bag.
- Throw the bag in the garbage.
If you do it right, you shouldn't touch the plant at all, just the plastic. Nevertheless, to be on the safe side, cover up in the manner described above before you get started—gloves, long sleeves, the works.
Finally, throw the poison ivy-filled bag into the garbage. Don't compost it, and whatever you do, don't burn it. Burning poison ivy releases urushiol into the air. Breathing it in is even worse than having it on your skin, and virtually guarantees a trip to the hospital.
The Plastic Sheet Strategy
You can also get rid of poison ivy vines just as you would any other weed: cover them with black plastic. Like all plants, poison ivy needs light and oxygen in order to live, and black plastic sheeting will eliminate both. So that it won't be an eyesore, consider covering the plastic with organic mulch, such as compost, shredded bark, or leaves.
Mowing poison ivy is not advisable. Although repeated brush hogging will eventually kill it, cutting it down with your lawn tractor, push mower, or weedeater will spatter urushiol into the air, which could get into your eyes, mouth, nose, or a cut on your body. Levels of urushiol in poison ivy are at their peak in spring and summer.
Sometimes manual solutions just don't work, particularly if you're plagued by a swarm of poison ivy shrubs or an unholy intermingling of shrubs and vines.
You smother them; they revive. You bag them and grab them, and in a few weeks, they're waving those three leaves (or is it just the middle leaf?) at you once again.
When that happens, you may decide to reach for organic or synthetic herbicide. Whichever type you use, be sure to apply it carefully so that you don't kill or damage nearby plants. To minimize danger to yourself and surrounding plants, add a shield to your sprayer nozzle and cover surrounding plants with plastic sheeting, newspaper, or cardboard. Alternatively, you could snip poison ivy at its base and apply herbicide with a disposable sponge brush directly to the cut.
An application of white vinegar that's 10 to 20 percent acetic acid will kill small poison ivy vines and shrubs. (Common household vinegar is 5 percent acetic acid.) Strong vinegar will also burn you, so please wear protective glasses and clothing when you apply it.
Some people also advocate an organic herbicide comprised of salt, water, and soap.
Sometimes, it takes a systemic synthetic killer like glyphosate or triclopyr to bring down a tough patch of poison ivy. As with any herbicide, be extremely careful during application to avoid killing nearby plants. Glyphosate kills woody and nonwoody plants; triclopyr kills everything but grass and sedge.
Follow the directions on the label carefully. Then, after the number of days prescribed, put your protective gear on and remove the dead poison ivy.
Neither herbicide remains active in the soil for long, so you can replant the area within a short time—before a new crop of poison ivy moves in.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.