Poison Sumac

What is poison sumac?

Poison sumac is a native shrub or small tree of eastern wetlands, and it carries the same skin-blistering oil as poison ivy and poison oak. Because it has long leaves with many leaflets instead of three, the familiar three-leaflet warning does not help here, so poison sumac identification depends on a different checklist: wet ground, smooth leaflet edges, red leaf stalks and pale berries that hang down.

Most people never meet it, because it lives in swamps, bogs and soggy thickets with little foot traffic. The risk comes when you clear brush along a wet woodlot or stream, cut a trail through a marshy area, or burn a brush pile with a few stems mixed in. It is also easy to confuse with the harmless sumacs of dry, sunny ground, which leads people to fear the wrong plant and overlook the right one.

Poison Sumac identification: what to look for

Start with the setting, then the leaf. Poison sumac almost always grows in wet, acidic soil. Count the leaflets, check the edges for teeth, note the color of the leaf stalk, and look at the berries, all by eye; every part of the plant can cause a rash.

• Leaves: Alternate, pinnately compound leaves with 7 to 13 elliptic to oval leaflets, about 2 to 4 inches long, paired along a central stalk with one at the tip. Edges are smooth, with no teeth.
• Leaf stalk: The central stalk is smooth and pale to bright red, and new growth may be reddish. Fall color is bright orange to red.
• Stems and bark: Smooth, reddish-orange to coppery young stems dotted with dark pores; older bark is smooth and gray-brown. Cut stems ooze a dark sap that blackens in air.
• Flowers: Tiny greenish-yellow flowers in loose, drooping clusters in early to mid summer, on separate male and female plants.
• Berries: Smooth, round, whitish to cream berries in hanging clusters from late summer through winter. Harmless smooth sumac, by contrast, carries red, hairy fruit.
• Size and form: An open-crowned shrub or small tree up to about 25 feet, often with several stems from the base.

Where it grows in the United States

Poison sumac ranges through the eastern and east-central United States and into eastern Canada, from Nova Scotia, Quebec and Ontario southward. It is hardy roughly in USDA zones 3 through 8. In North Carolina, NC State reports it mainly on the coastal plain and only rarely in the Piedmont and mountains.

Penn State describes it as a true wetland plant, and NC State lists bogs, marshes, swamps and riverside thickets with acidic, moist soil that may flood now and then. That is the biggest clue for homeowners: a sumac on a dry, sunny roadside or a well-drained hillside is very likely one of the harmless species. Around homes, expect poison sumac only where the ground stays wet, such as swampy woods or a marshy stream bank.

Poison Sumac look-alikes

A few plants get mixed up with it:

• Staghorn sumac (Rhus typhina): Harmless. Its stems are fuzzy and its leaflets have toothed edges, while poison sumac has smooth stems and smooth-edged leaflets. Penn State notes staghorn sumac often gets blamed for poison ivy growing beneath it.
• Smooth sumac (Rhus glabra): Harmless. Leaves carry many more leaflets (often well over 13), each sharply toothed, and the fruit is red and covered in sticky red hairs. It grows on dry slopes, prairies and disturbed ground and does not like wet soil.
• White ash (Fraxinus americana): Also has feather-like leaves with several leaflets, but ash leaves grow in opposite pairs on the twig and the tree makes winged seeds. Poison sumac leaves alternate along the stem and it bears berries.

How to get rid of poison sumac

Pulling, digging and mowing: In a wetland you rarely visit, the safest choice is often to leave poison sumac alone and steer people away from it. Where it must go, small plants can be dug out with a shovel or digging fork, getting as much root as possible and checking back for sprouts. Larger shrubs are usually cut near the ground and the stump treated right away (see below), because cutting alone lets the plant resprout from the base. Before you start, put on long sleeves, long pants, closed shoes with socks, eye protection, and waterproof gloves over disposable nitrile gloves. Bag the cuttings for the trash. Never compost or burn them. Wash tools with warm water and detergent, clean pruners with rubbing alcohol, and wash work clothes separately in hot water.

Cultural control matters most, because the right conditions keep it from coming back.

• Learn the plant and point it out to family members and anyone who works the property, especially around ponds and wet woods.
• Keep foot paths, mowing and brush clearing away from known patches where possible.
• Never put poison sumac in a brush pile that will be burned; the smoke can cause severe lung injury.
• Revisit cleared spots to catch sprouts from the base or new seedlings and treat them while small.

Herbicides: For woody plants like poison sumac, Penn State recommends the cut-stump method: cut the stem just above the ground and, within about 15 minutes, paint or spray a concentrated systemic herbicide such as triclopyr or glyphosate onto the fresh cut. It works best from late summer through fall and poorly in spring. Foliar sprays of systemic herbicides can also work on actively growing plants with plenty of healthy leaves, but glyphosate is nonselective and will injure nearby plants, while triclopyr targets broadleaf plants. Watch for resprouts and re-treat. Because poison sumac grows in wetlands and near water, use only a product and formulation whose label specifically covers wet sites or water. The label is the law. If you hire someone to spray, make sure they hold your state’s pesticide applicator license; the rules for each state are in our pesticide applicator license guide.

Keeping it from coming back

Since the three-leaflet rule does not apply, learn the poison sumac checklist: wet ground, 7 to 13 smooth-edged leaflets, red leaf stalks and pale hanging berries. Near swamps or bogs, wear long sleeves, long pants, boots and gloves, and consider a barrier cream before you go out, as CDC suggests for outdoor workers.

If you brush against it, rinse the skin right away with rubbing alcohol, a poison plant wash or dish soap and plenty of water, and scrub under your nails. Wet compresses, calamine or hydrocortisone and an oral antihistamine can ease itching. Get medical help for a severe rash or one on the face or genitals, and call 911 for swelling or trouble breathing.

Questions we get about poison sumac

Similar weeds

Atlantic Poison OakToxicodendron pubescensPacific Poison OakToxicodendron diversilobumBermuda ButtercupOxalis pes-caprae