Poison Ivy (Toxicodendron radicans)

It’s always been with us but now, thanks to increased CO2 in the atmosphere, it’s thriving as never before (National Geographic). And that news is certainly confirmed by its success in my very own garden.

Readers at GardenRant offered some great real-life stories and recommendations to a story I wrote there about PI, and they’re incorporated here.

About the plant and the dermatitis

Poison ivy is found in most of North America and is surely our least favorite native plant. It famously has three leaves, and the plant can be trailing on the ground, climbing vertically, or even in shrub form. Over 50 birds eat its seeds, which appear in the fall and may last through the winter.

Touching poison ivy can cause dermatitis with swelling and blistering, caused by its toxic oils. Those oils can remain on the skin or clothing for an indefinite period and by that I mean forever. (Botanists have gotten dermatitis from handling the dried leaves of 100-year-old plants!)

Contrary to common belief, the fluid in the blisters does not cause dermatitis or spread the problem — it’s the spreading of poison ivy OIL that’s the problem.

Sensitivity to poison ivy increases with each exposure, so don’t anybody assume you’re immune because the next run-in with it could change all that. Ultimately, one’s sensitivity could become so bad that contact with poison ivy results in a systemic reaction, which I don’t even want to contemplate.

Getting rid of it

Shallow-rooted, it’s not hard to dig up, as long as you cover your skin and wash all clothes and tools afterward. One reader told us she uses “Ivy Block to treat my face before I pull up poison ivy. I wear a painter’s mask, goggles, painters coveralls and rubber gloves over garden gloves for the job.” And a garden writer wrote to declare that “The depths of misery for poison ivy sufferers is unmatched in my opinion.” Wow — just shows that for some people it’s waaay worse than for others.

A highly herbicide that comes highly recommended by gardeners and experts alike for killing poison ivy is Vine-X. Jeff Ball wrote to tell us it’s safe “because it comes in a container with a small applicator brush on the top. The material comes out only through the brush, which makes it very easy to get the stuff only on the plant to be dispatched. What’s really neat is the weed dies when only six or eight inches of the base of the stem are brushed with the herbicide. It also works in the winter.”

And horticulturist Jeff Gillman wrote: “Let me second the effectiveness of Vine-X — the active ingredient is triclopyr, which you can buy in many other herbicides — but that brush is really handy and environmentally smart (keeps the herbicide where it belongs).”

Glyphosate, the active ingredient in Roundup, is also a very effective herbicide against poison ivy, especially when used late in its growth cycle, presumably late summer. It kills anything it’s sprayed on, so not to be used on a windy day. And because it can kill fish and frogs, it should never be used near water.

If you’re too allergic to deal with it yourself, you might hire someone else to do it, like the Poison Ivy Horticulturist near Philadelphia, or a landscape maintenance service in your area.

And you probably know this but it’s worth repeating: don’t EVER burn it. The smoke and fumes can and do enter the lungs of people and animals even at considerable distance away and make them very sick.

If you touch it

Some sources recommend rubbing the affected area with jewelweed, which sometimes grows near poison ivy. Its stems and leaves should be crushed and rubbed on the sap. One expert keeps it handy in ice cube form.

Ohio State advises “If contacted, affected areas should be washed immediately with soap and water as well as any clothing or objects that may have come in contact with the oil. This activity will not decrease the severity of the reaction, but it will lessen the chance of spread.” Hmm, not encouraging.

But this is more promising: UC-Davis says “After coming in contact with the allergen, the best way to prevent skin irritation is to pour a mild solvent, such as isopropyl alcohol (rubbing alcohol) over the exposed area and then follow this with plenty of cold water (warm water enhances penetration of the oil) within a few minutes of exposure. If isopropyl alcohol is not available, just wash with lots of cold water. But you need to wash within 5 minutes of exposure to prevent a rash. Even if it is too late to prevent the rash, washing the skin to remove excess plant oil will keep the rash from spreading.

“Using only a small amount of water or disposable hand wipes is more likely to spread the toxin than remove it. Soaps can be used to wash, but only if used with copious amounts of water; otherwise, they too will spread the toxin.”

One GardenRant commenter told us she uses cool water and Dawn dish-washing detergent within an hour of exposure to remove the ivy oil and that it works like a charm.

Tecnu makes a wash you use within a few hours of exposure to remove the toxic oils and readers told us it usually usually prevents the rash altogether. Garden writer Rich Pomeranz wrote: “Tecnu is the BEST! I used to have a bout or two of poison ivy every summer until I found this stuff. Now if I think I touched any of the plant I immediately wash the affected area with tecnu using, and here is an important detail, the hottest water I can stand. When I do this I never get the rash.” So, water temperature is definitely a detail over which disagreement persists.

If you’re scratching

Again from UC-Davis “If a rash develops after exposure to poison oak, the use of a product called Tecnu, which is sold at most drug stores, will relieve the itch and reduce the rash. When applied once a day, it stops the itching for most of the day and clears up the rash in about 7 days.”

And a reader wrote to recommend regular old hand sanitizer because it brought “instant relief” to her itching.

Photo credit.