PL. —Toxicodendron vernixBotanical illustration — drop image
Toxicodendron vernix

Poison Sumac

SpringSummerFallWinter
4a9bHardiness zone
Background

Poison sumac is a native North American woody shrub or small tree that grows almost exclusively in saturated, acidic soils — bogs, swamps, and poorly drained bottomlands across the eastern United States and Canada. All plant parts contain urushiol, the same oil responsible for reactions caused by poison ivy and poison oak, and poison sumac is generally considered more potent than either. Smoke from burning plants is especially hazardous and can cause severe respiratory injury.

It reaches up to 9 m (30 ft) in wetland sites where few other woody plants establish. Compound pinnate leaves turn vivid orange, red, and purple in fall. Loose clusters of waxy white to gray berries persist into winter and are consumed by more than 20 bird species — including yellow-rumped warblers, woodpeckers, and wild turkeys — which disperse seeds broadly. The plant spreads by root suckers as well, making removal labor-intensive and high-risk without proper protective gear. It is also known as thunderwood, particularly in the southern United States.

Despite its toxicity to humans, poison sumac functions as a native component of wetland edge communities, providing reliable winter fruit for migratory and resident birds. Gardeners managing wetland margins should learn to identify it by its smooth gray stems, evenly paired leaflets, and pendant berry clusters on red stalks.

Care guide
SunPart shade to full sun
WaterMoist to wet
SoilMoist, wet, acidic
Spacing10–20 ft
Height6–30 ft
Zone4a – 9b
Native RegionAL, AR, CT, DE, FL, GA, IL, IN, KY, LA, ME, MD, MA, MI, MN, MS, MO, NH, NJ, NY, NC, OH, PA, RI, SC, TN, TX, VT, VA, WV, WI
Frost hardy
Seasonal tasks
winter
watchBare stems and persistent berry clusters on drooping red stalks allow winter identification; all parts remain toxic through dormancy. Flag plants for early spring treatment.
spring
cutRemove seedlings by cutting at or below the soil line while wearing chemical-resistant gloves, long sleeves, and eye protection. Bag all cuttings; do not compost or burn.
watchScout wetland margins and boggy areas in early spring for emerging compound leaves; identify plants before full leaf-out makes access difficult and surrounding vegetation dense.
summer
watchCheck fence lines, wetland edges, and areas beneath bird activity for new seedlings; bird-dispersed seeds germinate readily in moist, open ground.
cutFor established shrubs, cut main stems close to the ground while wearing full protective gear, then immediately treat the cut surface with a systemic herbicide such as triclopyr or glyphosate to prevent resprouting from the root crown.
fall
watchMark fruiting clusters of white-gray berries in fall before birds disperse seeds; targeted removal of berry-bearing stems before dispersal reduces future seedling pressure.