Footsteps in the Forest

We think that it’s wise for nature lovers to familiarize themselves with the common species they’ll encounter during hikes, camping trips and other adventures in natural areas.

This includes things like the dangerous snakes in your state and some of the most common tree species in the eastern United States, but you’ll also want to learn to identify poison ivy (and its close relatives).

Doing so is actually pretty easy, and it’ll serve as our focus below.

We’ll explain what poison ivy looks like, outline some of the most common places in which you may see it and point out some interesting things about poison ivy rashes.

Quick Info: What Does Poison Ivy Look Like?

We’ll provide more detail about the appearance of poison ivy below, but here are the key takeaways.

Poison ivy:

• Grows as a ground cover, climbing vine or standalone shrub
• Has leaflets grouped in threes
• The central stem of each leaf is obviously longer than the lateral stems
• Each individual leaflet is almond-shaped
• Leaflets may or may not bear teeth
• Leaves are often reddish in spring, before turning green in the summer
• Leaves turn shades of yellow, orange or red in the fall
• Female poison ivy plants produce green to white, berry-like fruit
• Vines are often covered in small “hairs”

Note that poison ivy has several close relatives, such as Atlantic poison oak (Toxicodendron pubescens). some of the characteristics listed above do not apply to its relatives. We’ll explain some of these exceptions in more detail in the following section.

Poison Ivy Description and Identification

Poison ivy is a common woody vine or shrub, with leaves that are often described as occurring in groups of three.

But while helpful, this description is slightly incorrect.

Poison ivy is better described as a trifoliate plant, with compound leaves that are divided into three parts, called leaflets. Each of the “leaves” you see is actually a leaflet. The entire group of three comprises a single “leaf.”  

The central leaflet has a longer stem than either of the two lateral (side) leaflets. The lateral leaflets may have very short stems, which are hard to see at all.

Each leaflet is often described as being somewhat almond-shaped. These leaflets lake any true lobes, but some may have a few large “teeth” around the edge. It is important to note that some of poison ivy’s close relatives – such as Atlantic poison oak – often do have lobes.

The surfaces of poison ivy leaflets are smooth (though you’ll want to avoid touching them to verify) and free of hairs.

Each leaflet is generally about 1 to 5 inches long, though those found on mature specimens may occasionally reach nearly 1 foot in length.

The actual leaves are arranged in an alternating pattern down the stem or vine. This helps observers distinguish the plant from some of its lookalikes, such as the ash-leaf maple (Acer negundo).

Poison ivy is a deciduous plant, meaning that it sheds its leaves in the autumn. In the spring, new leaves often have a red appearance, though they’ll quickly become green over the next few days or weeks. Some leaves may become quite glossy by the summer.

In the fall, poison ivy leaves change to yellow, orange or red, and they’re often quite a visual treat.

When it takes the form of a vine, poison ivy may grow along the ground or scale tree trunks or other vertical surfaces. In both cases, the vines often bear small fibers called adventitious roots. These structures help anchor the vine to the surface its climbing and give it a “hairy” appearance.

These hairy vines offer an important identification clue during the winter, when the plant is bare.

Poison ivy is a dioecious species, which means that individuals are either distinctly male or distinctly female.

Both sexes produce flowers that are broadly similar at a glance. But on closer inspection, one may notice that the male flowers have five obvious stamens, which are coated in thick yellow pollen.

By contrast, female flowers lack well-developed stamens, though they have relatively prominent three-lobed pistils found at the center portion of the flower.

Once fertilized, the female flowers will produce pale green fruit, which turn pale yellow or white upon maturity. The fruit generally grows in clusters, though each individual fruit is small and berry-like (they are technically considered drupes).   

Poison Ivy Image Gallery: See the Plant for Yourself

If you really want to learn how to identify poison ivy, the best thing to do is just start looking at photos. We’ll help below, by sharing images of the entire plant, as well as its individual components. We’ll also share some comparison photos, so you can see how it differs from some of its lookalikes and common associates.

Poison Ivy Photos: The Entire Plant

As mentioned, poison ivy can grow in any of three forms: a ground-covering vine, a tree-climbing vine, or as a free-standing shrub. Be sure to familiarize yourself with all three.

Poison Ivy Photos: The Leaves

The leaves of poison ivy may all follow a few key rules, such as bearing three leaflets and having a central stem that is longer than the lateral stems. But they still vary in many ways, so it can be helpful to review an assortment of photos.

Poison Ivy Photos: The Flowers

The flowers of poison ivy plants are quite small and easy to overlook. Nevertheless, they can provide important identification clues, once you familiarize yourself with them.

Poison Ivy Photos: The Fruit

Poison ivy fruit are typically easiest to notice in the fall or winter, but you can find them in the summer if you look carefully.

Poison Ivy Photos: The Vine

Not all hairy vines are poison ivy, but it is typically wise to simply avoid touching any that do have a hairy appearance.

Poison Ivy Classification: Poison Ivy and Its Relatives

Most people think of “poison ivy” as a single species, but botanists recognize several different species.

They’re all very closely related, and they are all capable of triggering the infamous rash, but they do exhibit subtle – and in some cases, not-so-subtle — differences.

We’ll outline the various species as they’re currently recognized by most sources (different authorities treat the group in slightly different ways). But because the vast majority of readers are really only concerned with learning to identify and avoid the plants, we won’t go into great depth.

• Eastern poison ivy (Toxicodendron radicans): The representative of the group we’re primarily focusing on, this one is found throughout most of the eastern and southern United States. This form likely exhibits the most flexibility with regard to growth habit, as it may take the form of a vine, ground cover or standalone plant. Distinguish this plant from western poison ivy by noting small hairs on the fruit.
• Western poison ivy (Toxicodendron rydbergii): Perhaps the most widespread (if not the most commonly encountered) member of the group, this species grows as a shrub and features irregular, sinuous leaf edges with prominent leaf veins. The fruit of this plant lack hairs.
• Atlantic poison oak (Toxicodendron pubescens): A shrubby species which generally produces hairy, distinctly lobed leaflets, which are easy to mistake for the leaves of the white oak tree (Quercus alba) – hence the specie’s common name.
• Pacific poison oak (Toxicodendron diversilobum): As its specific name (diversilobum) hints, the Pacific poison oak can produce leaflets that vary in shape. Some are scalloped, whereas others are toothed or lobed. These plants even produce leaves with five to seven leaflets on rare occasions. It can grow as a shrub or tree-climbing vine.
• Poison sumac (Toxicodendron vernix): While it’s related to poison ivy and the other species mentioned here, the poison sumac is quite a bit different. For starters, it often grows as a tree, and it’s also quite a bit more elusive – it’s generally not encountered as often as poison ivy or Atlantic poison oak. And that’s a good thing too, as poison sumac often causes more serious rashes. It’s easy to distinguish this species from the others, as it bears leaves with 7 to 13 leaflets.

Again, this only represents the current thinking on the subject. Botanists and taxonomists may alter their treatment of this group in the future.

None of this is particularly important to hikers and backpackers – it’s only important that you learn to recognize the plants.

Poison Ivy Range and Habitat: Where Does Poison Ivy Grow?

Poison ivy is relatively widespread and common. Most hikers and campers living in the U.S. are at risk of encountering poison ivy (or one of its relatives) while enjoying the great outdoors.

But that doesn’t mean you can find each of these species in every location, nor are these species common in all habitats. So, it’s important for nature lovers to learn the places in which it is particularly important to be on the lookout for the plant.

We’ll share the range and typical habitat of poison ivy and its relatives in the table below.

Species	Range	Habitat
Eastern Poison Ivy (T. radicans)	All of the U.S. east of the Rocky Mountains. It’s also found in eastern Canada and portions of Mexico.	Adaptable, but forest edges are its preferred habitat. May also be found in forest understories, fields, riparian areas and disturbed/suburban locations.
Western Poison Ivy (T. rydbergii)	Most of the United States, except for the southeast and California. It’s also found across much of Canada.	Forests are the preferred habitat, but it’s also found in fields and disturbed/suburban habitats.
Atlantic Poison Oak (T. pubescens)	The southeastern United States, north to Virginia and west to Texas.	Primarily forests, but it is adaptable and grows in fields and scrubby areas too.
Pacific Poison Oak (T. diversilobum)	The west coast of North America, north to British Columbia and south to the Baja peninsula.	Variable, including both forests (with sufficient light penetration) and open, exposed habitats.
Poison Sumac (T. vernix)	Scattered locations throughout the eastern United States and southeastern Canada.	A bit of a habitat specialist, poison sumac is only common in swamps and peat bogs.

Do note that exceptions and outliers occur in the natural world. Occasional specimens show up far outside their range (usually courtesy of a traveling bird who has inadvertently transplanted seeds via its digestive tract).

So, if you’re looking at a plant you suspect to be a member of the poison ivy clade growing outside its normal range, err on the side of caution and give it a wide berth.

Poison Ivy Rashes: Poison Ivy & Humans

Learning to identify plants and trees is a valuable pursuit, but it’s not especially necessary for enjoying the outdoors.

It doesn’t really matter if you can distinguish a southern red oak tree from a northern red oak tree unless you simply want to be able to do so.

However, poison ivy and its relatives are a different matter.  

You do need to know how to identify these plants, as they can cause serious health problems in some cases.

The most common problem these plants cause is a skin rash. However, poison ivy can also cause things like lung damage in some cases.

We’ll dive into the subject and explain everything you need to know below.

The Poison Ivy Rash

After contacting urushiol, the body of a sensitive individual will begin launching an attack to deal with the foreign substance. But as occurs in allergic reactions – the response is out of proportion with the threat.

The result is often a very red, itchy and occasionally painful rash in the region that contacted the urushiol. Blisters may form in some cases. If the urushiol becomes airborne in the form of smoke (such as often occurs when poison ivy is burned), sensitive individuals may experience an allergic reaction in their lungs. This can be fatal in some cases.  

Note that because urushiol is an allergen rather than a true toxin, it takes some time for a rash to appear.

So, while a stinging nettle (for example) may cause you to experience immediate burning or itching, poison ivy rashes usually won’t manifest until hours or days have passed. You may brush up against some poison ivy while hiking to your campsite Friday night and remain blissfully unaware of the contact until you start noticing an extremely itchy rash while sitting at work on Monday morning.

Fortunately, the rash itself is not contagious, nor does it “spread.”

It may develop slowly, which can give people the impression that they’ve spread the rash by scratching. But assuming you’ve bathed several times between contact with the plant and the onset of the rash, it shouldn’t be possible to spread the rash in this manner.

Like many other allergic reactions, the severity of an allergic reaction to urushiol can change over time. People who don’t appear to be allergic to poison ivy today may find themselves covered in a rash after contacting the plant tomorrow.

Point being: It’s always wise to avoid contact with poison ivy and its kin. Just because you’ve never been affected by it doesn’t mean you’ll always be able to say the same thing.

The rash itself can last days to weeks, depending on the severity of the reaction.

The Poison Ivy Rash: Prevention & Treatment

As is so often the case, it’s easier to prevent poison ivy rashes than it is to treat them. Fortunately, this is pretty easy to do – just avoid contact with poison ivy and its relatives.

Some of the best ways to prevent poison ivy rashes include:

• Learn to identify poison ivy, poison oak, and other related plants and avoid them when enjoying time in natural areas (though you should remember that these plants do occur in residential areas too).
• Wear long pants and sleeves when hiking through the forest or areas in which these plants are found.
• Wash your hands as soon as you possibly can after finishing your time in the great outdoors. Be sure to rinse thoroughly and clean the area under your fingernails.
• If water is not available, rubbing alcohol or alcohol-based hand sanitizer may help break down or remove urushiol from your skin.
• You can consider using a commercially produced poison ivy wash, though the efficacy of these products varies.
• The CDC reports that Bentoquatam-based creams or lotions may provide some protection and prevent urushiol from contacting your skin.
• Wash your clothes in a separate load immediately upon returning home. Use hot water while doing so.
• Use care with any tools or other items that may have contacted poison ivy – the oil may linger on these surfaces for years.

Of course, none of this is helpful for those who’re already experiencing a rash. At best, they’re just good tips to embrace on your next trek through the forest.

We are not medical or health-related authorities. If you suspect you are having an allergic reaction to poison ivy contact your doctor or dial 911. However, dermatologists and other medical professionals often recommend the following home remedies:

• Oatmeal baths are sometimes helpful for soothing itchy skin.
• Others find baking soda baths to be helpful.
• Cold compresses applied for 20 to 30 minutes at a time help some people feel better.
• Your doctor may recommend taking an oral antihistamine.
• Some sufferers find calamine lotion helps soothe the itching.

If you’re experiencing a severe allergic reaction, your doctor may prescribe steroid medications.

Poison Ivy, Wildlife & Ecology: The Environmental Benefits of Poison Ivy

It’s important to note that humans tend to revile poison ivy, but the plant plays a variety of important roles in natural ecosystems.

One of the most intriguing things about poison ivy and its kin is the fact that it doesn’t trigger an allergic reaction in many wild animals. It rarely affects domestic animals either, though urushiol can contaminate fur, which means you may get a poison ivy rash after touching a dog who’s run through poison ivy.

In fact, poison ivy is a vital resource for many animals.

For example, many birds consume the plant’s fruit. The vines provide habitat and cover for small reptiles, amphibians, and invertebrates (who also feed upon the plant’s nectar). Rabbits, black bear and mule deer consume the leaves and twigs on occasion.  

In total, 61 species rely on poison ivy (or its relatives), according to one of the best nature books we’ve ever cracked open. This includes bluebirds, mockingbirds, juncos, chickadees, catbirds, and thrashers, among others.

Interestingly, common flickers and other ant-eating woodpeckers are often particularly fond of poison ivy berries.

But poison ivy’s ecological impact goes beyond providing food and shelter for wildlife.

The plant also helps to compete with invasive species, which helps protect ecosystems from long-term harm. It can also help slow erosion when it grows as a ground-hugging vine.

And of course, like all green plants, poison ivy helps remove carbon dioxide from the air and produce oxygen.

So, just remember that while humans are wise to avoid poison ivy entirely, it still deserves a place in the natural world.

Poison Ivy FAQ: What Does Poison Ivy Look Like and Other Common Questions

Still have questions about what poison ivy looks like? Curious about some of the plant’s properties? We’ve rounded up a few of the most common questions people Google and answered them below.

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Poison ivy, poison oak, and poison sumac are important plants that are medically significant and common across much of North America. So, it behooves hikers and other outdoor enthusiasts to learn to identify them.

We hope we’ve made that easier, but don’t hesitate to share your poison ivy identification questions in the comments below!