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Poison Sumac

Poison sumac on water's edge

Poison sumac (Toxicodendron vernix) is a native plant that grows exclusively in very wet or flooded soils, usually in swamps and peat bogs. Every part of the plant contains an oil that inflames skin and results in painfully itchy blisters and rashes. Inhalation of smoke from burning leaves and vines is extremely hazardous.

Identification

Poison sumac is a small slender tree, or multi-stemmed shrub, with grey bark and large compound leaves with 7-13 leaflets. The leaflets are not toothed and are smooth without hair. The central leaf stem may be reddish. The leaves are often held upward and appear somewhat stiff. They look somewhat like ash leaves. Clusters of small yellow flowers are followed by small whitish berries - almost identical to those of poison ivy. After the leaves fall, the distinctive hanging clusters of dull white berries may persist well into winter.

Both staghorn sumac and smooth sumac have soft compound leaves with 11 to 31 finely toothed leaflets. They have red berries held in upright clusters above the leaves. Staghorn sumac has fuzzy new twigs like antlers in velvet, and can grow to 25 feet tall and 6 inches or more in diameter. Smooth sumac is much smaller, 10 feet tall at most. Both of these common species usually grow in groups of small trees, actually clonal colonies from a single spreading rootstock. Neither staghorn nor smooth sumac are harmful to skin.

Where is poison sumac located?

Poison sumac is found across New York State, but is fairly uncommon. It grows only in certain types of wetland, specifically, fens, calcareous marshes, and open wooded swamps. It may grow on sedge tussocks, in standing water and or in saturated soils. Poison sumac occurs as single scattered individuals, not in clonal groups. It never grows on dry upland sites such as typical roadsides, fields and sunny hillsides where staghorn and smooth sumac thrive.

Only people such as hunters, birdwatchers, naturalists and others who go deep into wooded swamps, are ever likely encounter poison sumac.

Why is poison sumac dangerous?

Poison sumac in a wetland

Unlike poison ivy, poison sumac is comparatively rare, and most people have never seen it. Since the sap of poison sumac has the same allergenic oil, urushiol (you-ROO-she-all), as that of poison ivy, the two are frequently mentioned together as plants to avoid. Urushiol is a potent allergen and even microscopic amounts can cause skin reactions ranging from an itchy rash to severe blisters.

Look alike plants

Many people remember the name "sumac" in conjunction with poisonous plants, and worry that all sumacs must be toxic. However, the common sumac species which grow along roads and in fields are not poison sumac. They are either staghorn or smooth sumac, both species quite harmless to touch. Poison sumac is a wetland species and never grows in the dry upland areas, where staghorn and smooth sumac are common along sunny roadsides.