Poison sumac has a fierce reputation, and deservedly so. It’s not as common as people think, and there are a lot of lookalikes, but encountering it is an unforgettable experience.
Touching the plant can cause a painful, irritating rash that can blister and last for weeks. Once the oil is on your clothes or skin, it can spread to other parts of your body, clothing, furniture, people, or animals that you come in contact with.
This plant has the same toxic oil that is found in poison oak and poison ivy, but poison sumac causes worse symptoms in people because it’s more allergenic.
Poison sumac isn’t found in the western parts of North America. It only grows in the Northeast, Midwest, and Southeast.
It is indigenous to moist or wet areas. It thrives in swamps, next to rivers, and in bogs. You won’t ever find poison sumac in a dry area, so if you see a plant that you suspect to be poison sumac in an arid region, it’s probably a lookalike, such as staghorn sumac. You won’t see it growing along roadsides, in fields, or at forest edges.
It only grows as single specimen. It doesn’t grow in groups, so if you find a patch of sumac, it’s probably a different species.
Look for it near lakes and rivers, in swamps and bogs, in the understory of pine forests, and as a weed in cultivated ponds.
Its limited environmental tolerance means that most people won’t run into the plant unless they go hiking, foraging, or exploring wilderness areas.
How to Identify
This plant can take on a small tree or shrub-like growth habit and grows anywhere from five to 20 feet tall when mature. It has an open, sparse growth habit.
It has gray bark and large, alternate, pinnate compound leaves. Compound leaves are those that have multiple smaller leaves (called leaflets) that make up one larger leaf. In this case, the leaves of poison sumac are made up of 7-13 hairless leaflets with a smooth margin on a reddish stem. This reddish stem helps you differentiate poison from other sumacs.
The leaves are elongated and stiff, and are held upright on the stem. They are bright orange in the spring and then turn dark green on glossy on the surface with a lighter green underside. In the fall, the leaves turn reddish-orange or dark red.
The plant develops yellow blossoms in late spring that form in large clusters at the end of long stems. These give way to small, green berries in early summer and fade to dull white berries in the fall.
Don’t take your cues from birds and other wildlife. They can eat the berries without seeming to suffer any effect from the urushiol.
The challenge with identification in the winter is that the plant is deciduous. It drops its leaves, leaving behind the bare stem. But even coming in contact with the bare stem can cause symptoms.
Ash trees (Fraxinus spp.) is a tree that can resemble poison sumac. There are several native species in North America and many more important species that are cultivated in home gardens. The plant on this list have escaped cultivation and can be found in wilderness areas.
Ash trees have opposite leaves, and they lack the red stem. They don’t form berries. Instead, they develop winged samaras.
Poison ivy is mistaken for poison sumac, but the plants are easy to tell apart. The only similarity is that the berries on poison ivy and poison sumac look identical. They are both dull white in the fall. But the leaves on poison ivy come in groups of three and may have smooth or faintly toothed edges. The flowers are white.
Staghorn sumac (Rhus typhina) is a species that has red berries, making it easy to tell from the poisonous one. The leaves on this species has finely toothed margins. Each compound leaf is composed of 11-31 leaflets.
The young twigs have a fine fuzz on them, giving them a resemblance to staghorn ferns.
Smooth sumac (Rhus glabra) can also be confused with poison sumac. As the name suggests, the leaves of this species are softer and smoother than poison sumac. They have finely toothed margins. The leaves are made up of 11-31 leaflets. The plant has red berries.
Winged sumac (Rhus copallinum) looks identical in all ways except that it has red berries and the leaves are made up of 9-23 leaflets. If you examine the plant closely, you will see small winged rachis along the stem between the leaflets.
Tree of heaven (Ailanthus altissima) is indigenous to China, but it has escaped cultivation in North America. It’s invasive and can be found across the continent. While it looks extremely similar to poison sumac, including the red stems, the leaflets have notches on the tree of heaven.
Poison sumac contains urushiol (you-ROO-she-all). This is the same compound found in poison ivy, poisonwood, and poison oak. Only one nanogram of the oil can cause symptoms, and the average exposure is about 100 nanograms. And remember, poison sumac is more concentrated.
It would take just a quarter cup of the oil to give all 7.8 billion people on the planet a rash.
Urushiol is contained in an oil inside the plant, which is released when you brush up against it. It can even be carried on your clothes and then transfer to your skin once you touch the clothing.
A small percentage of people aren’t susceptible to the effects and might carry it on them, transferring it to a sensitive individual. Certain people may not show sensitivity initially, but after repeated exposure, they will develop symptoms.
You don’t have to eat or come in contact with the plant to experience the toxic effects. The compounds are released when the plant is burned. If there is a wildfire in a region where poisons sumac grows, avoid inhaling or coming into contact with any of the smoke.
Don’t ever put poison sumac into your burn piles.
The toxic compounds can remain on the plant for up to five years, so even cut plants leave you open to exposure.
It normally takes anywhere from 12-48 hours for the symptoms to appear, so you might not know that you’ve been exposed right away. The majority of people won’t react after their first exposure. It takes more than one to see symptoms. People may not know that they’ve been exposed the first time because there won’t be any symptoms.
If you are exposed to poison sumac, wash the area and all of your clothes as quickly as possible. Only the area that actually touched the plant will be contaminated. The oil doesn’t spread unless you manually move it by rubbing it.
You should also wash any tools, your pets, and anything else that might have come in contact with the plants.
Use warm water, as cold water makes it more difficult to remove the oil. It’s similar to using cold water to wash an oily pan. Warm or hot water is much for effective at removing oil. Use soap to help break up the oil. Cold water will work, but you will need to scrub a bit more.
If you don’t have access to warm water and soap, use isopropyl alcohol to cleanse the skin. Don’t head back out into the woods after cleaning your skin because the alcohol will remove your skin’s protective coating, leaving you even more exposed to any poisons out there.
Once you have washed everything, rinse it with cool water.
When you wash clothes, do so on the highest heat that your washer has and wash exposed clothes separately from uncontaminated clothes.
Those who live or hike in an area with poison sumac nearby should keep an over-the-counter product that contains bentoquatam in their medicine cabinet. Applying one of these products immediately after exposure will absorb the oil and reduce the symptoms.
Once you’ve been exposed and have symptoms, use a product that contains zinc acetate, hydrocortisone, or zinc oxide to ease the symptoms. A cold compress will also help.
If a blister forms, scratching it can introduce infection, but it won’t further spread the rash. Avoid scratching and use techniques to soothe the itching and burning, instead. Oatmeal baths are an effective way to temporarily ease the pain. A paste of baking soda can be applied to the skin. Oral antihistamines are effective at reducing the itching and irritation.
If your rash is oozing, bloody, or swollen, check in with a doctor. You might need professional treatment to ease the pain and prevent further infection.
If you have a fever over 100 degrees, if there is pus in the rash, if you can’t sleep because of the pain, if the oil gets into your eyes, ears, or mouth, or if it covers more than a fourth of your body, see a doctor right away. You should visit an emergency room if you feel like the exposure has reduced your ability to breathe.
About 15 percent of Americans are allergic to urushiol. Their symptoms will be much more dramatic and may require immediate treatment. If the rash shows up within a few hours of exposure, your eyes swell shut, or the blisters immediately form and burst, visit an emergency room immediately.
If your rash doesn’t resolve within a few weeks, see a doctor.
Poison sumac is rare in cultivated gardens, but if you have a large property with moist areas, you might find this plant on your property. If so, you should remove it to prevent accidental exposure and spread.
The best way to kill the plants is to pull it. Dress in protective clothing, including gloves, a mask, protective glasses, full-length pants, and long sleeves. Wear clothing that can be thoroughly washed after wear.
Then, cut the plant down if you can without coming into contact with it. Spray any remaining parts with glyphosate. Be sure to wipe or spray glyphosate on the remaining stumps to kill the roots.
It’s unlikely that the plants will die after one treatment. They will likely return at least once and probably several times. Keep treating the plants in the same way, and the roots will eventually be starved.