Think of it as the cockroach of the weed world. Poison ivy thrives in extreme heat and drought, and spreads through the most casual of contact. And like the crunchy insect pests, it can seem impossible to eradicate.
With all of summer's outdoor activity, we're scratching our information itch by looking at what threats the weed poses and how those threats can be avoided, or at least mitigated and treated.
What causes the itch? Urushiol oil is present in all parts of the poison ivy plant, and you'll know whether you've come in contact with it. Most people will develop an itchy, blistering rash. The more you've come in contact, the more allergic you're likely to become.
This rash might not develop until 12 to 24 hours after contact, when it's too late to take steps to prevent or lessen the effects, according to the American Academy of Dermatology.
How do I get it? Poison ivy's leaves grow in clusters of three, and it sprouts green-yellow flowers in the spring.
And there are surprising ways to become infected with it.
Many people get it by using gas or electric trimmers, says Trisha Shirey, an organic gardener and director of Flora & Fauna at Lake Austin Spa Resort in Texas. "They don't know they've weeded poison ivy and then they handle the trimmer head and get it that way."
What do I do after exposure? If you do notice you've been exposed to the vine, there are some immediate steps you can take:
■ Rinse your skin with lukewarm (not hot) water. It is possible to remove some of the oil.
■ Wash tools and any clothing that might have come in contact with the vine. Oil remaining on these surfaces can re-infect.
■ Bathe your pets. Although they won't develop allergic reactions, critters can transfer urushiol oil from their hair or fur to humans or onto surfaces with which owners might come in contact.
How do I ease the itch? Once a rash has developed, there are ways to ease your suffering, which can last for several weeks.
Don't worry about scratching the rash and then transferring it to other parts of your body. Once a rash has developed, that can't happen. Further outbreaks are a delayed result of the original exposure.
The dermatology association recommends oatmeal or baking soda baths, calamine lotion, cool showers and compresses, and oral antihistamines to relieve the intense itching. The academy warns that topical antihistamines, however, can make the rash and itching worse.
Shirey uses a skin cleanser called Tecnu, formulated to remove urushiol after exposure but before a rash develops. It's available at most drugstores and at TEClabsinc.com, which has a $2 printable coupon.
When the cleanser is not enough, she adds a white or green clay facial mask. She mixes the clay with water, applies it to the rash, allows it to dry, rinses it with cool water and repeats until the redness and irritation are gone.
"Usually within two or three applications, you'll see a marked difference in the irritation and itching," she says.
If you have a serious reaction that includes difficulty breathing and swallowing, or swelling — especially to the face — seek immediate medical attention. Severe cases might require steroid ointments or antibiotics.
How do I get rid of it? Getting rid of the noxious weed is tough but not impossible, Shirey says. The key is to literally nip the problem in the bud.
"One of the ways it gets transmitted is with birds, so you'll find young sprouts coming up here and there, and the best thing to do is to get that sprout out by the root before it has a chance to grow," Shirey says.
If you just trim, the weed will rebound to be stronger. "I'll use several layers of gloves and actually dig the root out and seal it up in a plastic bag and throw it in the trash," she says.
Shirey uses a dandelion weeder and says the roots come out more easily after a rain.
She also uses sprays but avoids commercial products, preferring her own eco-friendly mixture (see recipe below). She applies it on hot, sunny days (so rain won't wash it off) and begins to see the leaves become crisp and brown within 20 minutes. "Sometimes they will resprout, and so you hit them again until those roots just kind of tire out," she says.
Burning poison ivy is not recommended. "The oil is volatile in smoke," Shirey says, "and you can inhale it into your lungs and get very, very ill."