Don’t let poison ivy keep you indoors

Poison ivy is a poisonous wild plant native to much of Mexico, Canada and the U.S. As with any species of the genus Toxicodendron, all parts of the plant contain a toxic oil called urushiol that causes an itchy, irritating and sometimes painful rash in most people who touch it.

Sensitive people (approximately 70% of Americans) often develop allergic dermatitis within four to 48 hours of their skin coming in contact with the plant. This is typically characterized as a linear, itchy red rash that gradually blisters and weeps from clusters of pinprick-like bumps. The severity of the rash depends on how much urushiol was left on the skin, and areas with more of the oil may develop a rash sooner than other areas.

Safety Tips

While poison ivy can naturally be found growing in places where we live, work and play, there are effective ways to avoid that itchy red rash without staying inside. Consider the following safety precautions if you plan to spend time in an unmown or wild area:

• Cover up before you go. Wear long sleeves and pants, a hat, socks and shoes that cover your entire foot. This also plays into best practices for preventing skin cancer and bug bites. Dry, loosely woven fabrics are ideal for keeping the oil from reaching your skin. Alternatively, commercially available products such as poison ivy barrier creams or protection wipes can work as cover when applied as directed.
• Have a way to clean your skin immediately in case of exposure. Urushiol can be absorbed within 30 minutes of touching it, making quick clean-up important after suspected contact with the plant. This can be as simple as washing off at a nearby sink with soap and water. (No need for vigorous scrubbing, which can worsen exposure.) Keep a waterless poison ivy cleanser, such as IvyX wipes or a bottle of Tecnu and a towel, handy in your bag or vehicle for time in more remote areas.
• Do a quick scan for poison ivy before starting into an area. Look up, down and around as you move, since the plant can grow low as a groundcover, taller as a shrub or up a tree as a vine. This applies in wintertime too, since the oil remains in the leaves even after they fall off, as well as in the plant’s dormant woody stems. If you identify poison ivy up ahead, it’s probably best to turn around and go back the way you came. When handling vegetation, consider wearing gloves, tying back long hair and refraining from touching your face or eyes as a rule.
• Wash up afterward to remove any lingering urushiol. This can be an especially helpful habit for hikers, campers, gardeners and people who regularly work outside. Upon returning from the great outdoors, wash down your gear with soap or rubbing alcohol and water. Then do the same for your shoes, covering your hands with disposable gloves or plastic bags if needed. After that, change out of your clothes and send them straight to the laundry – wash with detergent in hot water separately from other clothes. Finally, take a normal shower (not a bath), avoiding complexion soaps with emollients or bath oils.

What Poison Ivy Looks Like

Poison ivy as a plant takes on many different forms and has a few look-alikes. Because of this, it can be tricky to recognize. In open, sunny situations like a field, it tends to grow densely as a bushy shrub. In the woods, poison ivy take on a more relaxed habit, spreading in low patches along the ground or up a tree as a vine.

A key identification characteristic of poison ivy is the leaf, which is actually compound and made up of three leaflets one to four inches long – hence the adage “leaves of three, let it be.”

Leaflets are variable in shape and size, even on the same plant, and can be smooth-edged, irregularly toothed or lobed, sometimes with a “thumb” that makes them look like pointed mittens. The new leaves of spring are often small, shiny and light green (even reddish or purplish) in color. Mature leaves are dark green, turning fiery red in autumn before falling away. Despite being deciduous, poison ivy vines can still be spotted in winter clinging to tree trunks by distinctive, intensely hairy woody stems.

Look-Alike Plants

Several plant species are often confused with poison ivy. Proper identification can be complicated by some of these plants growing interspersed with poison ivy in the wild, so observe closely! Here are the main ways to distinguish poison ivy from the rest:

• Virginia creeper is a woody vine. While young leaves sometimes have only three leaflets similar to poison ivy, mature leaves have five leaflets all connected at a single point.
• Boxelder is a tree that can look like poison ivy, especially as a seedling. However, any boxelder “leaves of three” are arranged oppositely along the stem rather than in an alternating pattern.
• Wild grape vines commonly grow in wild places as poison ivy does, but their leaves are not compound and grow singly along the stem.
• Fragrant sumac is a shrub in the same family as poison ivy with similar trifoliate leaves. Unlike poison ivy, none of its leaflets have stalks (petioles).
• Wild raspberry and blackberry are also shrubs with trifoliate leaves; these species can be distinguished from poison ivy because they have prickly stems, finely toothed leaf edges or both.
• Boston ivy is a vine that sometimes exhibits three-parted leaves; however, these are always young leaves – older leaves are three-lobed, but not separated like the leaflets of poison ivy.

Article courtesy of University of Nebraska Extension

Featured photo: Eastern poison ivy, by Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org