What Hikers Need to Know About Poison Ivy, Oak and Sumac


The last thing anyone wants in the middle of a long hike or a backpacking trip is to come in contact with poison ivy or other poisonous plants. Those who do off trail bushwhacking or hike on overgrown trails are especially at risk. The first step for prevention is for hikers to learn how to identify poison ivy as well as poison oak and sumac. When we can recognize dangerous plants we will be able to avoid them out on the trail.

Poison Ivy, Oak and Sumac Topics

poison ivy

The plant genus Toxicodendron gives us the poisonous plant species that are known for those nasty rashes. They are found throughout the United States except for Hawaii and Alaska.

  • Poison Ivy species includes T. radicans and T. rydbergii
  • Poison Oak species includes T. diversilobum and T. pubescens
  • Poison Sumac is known as T. vernix

Although nobody enjoys the aforementioned plants they actually are important to wildlife. Birds eat the berries in fall or winter when no other food is available and deer actually eat the foliage, berries, and twigs.

How to Identify Poison Ivy

One problem with poison ivy is that it is very adaptable and grows under many different conditions. Because of this fact it can look different depending on where it is growing.

  • 3-parted compound leaves (three leaves on the same small stem that comes off the larger main stem).

  • Leaves of three usually have jagged edges, sometimes with large notches, but never saw toothed (serrated).

  • Can be a low trailing shrub on the ground, an upright bush or a high free-standing shrub, or a climbing vine.

  • Vine form has hairy looking aerial roots.

  • Leaves can be both shiny and dull.

  • Leaves are green in the summer, red in the fall.

  • Poison ivy produces yellow or green flowers that turn into white, yellow or green clustered globular berries (fruit).

Poison Ivy Photos

poison ivy in low shrub form poison ivy berries hairy aerial vine roots poison ivy vine poison ivy map

Poison Oak Identification

  • Is very similar to poison ivy but it always grows erect.

  • Leaflets grow in threes and have variable leaf edges but may have lobes that resemble oak leaves.

  • Leaves have blunt tips.

  • Leaves are hairy on both sides.

  • Leaves turn red in fall.

Poison Oak Photos

poison oak poison oak with berries poison oak map

Identifying Poison Sumac

  • Grows as a shrub or small tree.

  • Leaflets have 7-13 pointed leaves that are NOT serrated.

  • White fruits.

  • Generally found in swampy areas.

Poison Sumac Pictures

poison sumac poison sumac map

Preventing a Rash

If you know ahead of time that you will come into contact with poison ivy, poison sumac or poison oak then preventing contact with the plant oils should be your main focus.
  • Cover up exposed body parts by wearing long pants that are tucked into your boots as well as shirts with long sleeves. Gloves would be helpful too.

  • Ivy Block lotion is an FDA approved skin protectant called bentoquatam. It provides some protection but it still is best to avoid contact with the plants.

How the Plant Oil Spreads

All parts of the plants are poisonous all throughout the year. Anyone can spread the plant oil (urushiol) to other people thru footwear, clothes, trek poles and any other hiking or backpacking gear that comes into contact with poison ivy. You could be exposed to the oil just from taking off your shoes after walking through some poison ivy. You can also get a rash from a dog that was into a patch of it as well. Oil that has rubbed off onto other things can remain potent for up to 5 years.

Some people are supposedly immune but sensitivity can develop over time. I know someone who bragged about his immunity to poison ivy over the years until finally one day when clearing the ivy from his fence line he got a mild rash on his hands and arms.

What to do if Exposed to Poison Ivy

Urushiol can penetrate your skin in minutes so be sure not to waste time if you know you have been exposed. The sooner you clean your skin the better chance you have of removing the oil. This can possibly lessen your rash and help prevent further spread.

  • Some skin doctors say to first clean the exposed skin with generous amounts of rubbing (isopropyl) alcohol to remove the urushiol. They also say that alcohol removes your skin's protection and that any new contact will cause the oil to penetrate twice as fast.

  • Secondly they say wash skin with water and no soap (bar soap may pick up some of the oil from the skin surface and move it around).

  • And third to take a regular shower with soap and warm water ... although this may not be possible on a trip so swimming will have to suffice. Make sure your soap is biodegradable and use it away from water sources.

  • You will also want to clean any gear with alcohol and water that may have come in contact with the urushiol.

  • There are various products that can help remove the poisonous plant oils.

    • Oak-n-Ivy Tecnu Cleanser has individual packets that are the perfect size for a 1st aid kit and can wash away the urushiol oils.

    • Tecnu also has an Extreme Medicated Poison Ivy Scrub that is supposed to be good.

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