Poison Sumac Plant Profile

Identifying the Toxic Poison Sumac Plant

What poison sumac's fall color looks like.
David Beaulieu

The poison sumac plant (Toxicodendron vernix) is not without its benefits, although other, non-toxic types of sumacs are better-suited for your yard. Wild birds eat the waxy white berries of T. vernix in winter when other food is scarce. Aside from its toxicity (and the rash that results from exposing your skin to it), the plant can be breathtaking in autumn. But the toxicity of poison sumac means that few people grow it in landscape applications—much more often, the goal is to eradicate it, not foster it.

The genus name, Toxicodendron, is composed of two Greek words and translates as "poison tree." Meanwhile, the species name, vernix, means "varnish." That is because, "A black varnish can be made from the sap, as in a related Japanese species," according to the National Audubon Society's "Field Guide to Trees."

Poison sumac is considerably more toxic than poison ivy and poison oak.

  • Botanical Name: Toxicodendron vernix
  • Common Name: Poison sumac, thunderwood
  • Plant Type: Woody deciduous shrub or small tree
  • Mature Size: Up to 30 feet tall
  • Sun Exposure: Full sun to part shade
  • Soil Type: wet and clay soils; prefers boggy locations
  • Soil pH: 3.6 to 6.5; acidic soils
  • Bloom Time: Spring and summer
  • Flower Color: yellowish green
  • Hardiness Zones: 3 to 8 (USDA)
  • Native Area: Eastern U.S. and southeast Canada

Identifying Poison Sumac

Learning how to recognize this plant is crucial to avoiding contact with it. Poison sumac can be quite a large shrub with a thick stem that makes the plant look more like a small tree than a shrub.Toxicodendron vernix has pinnately-compound leaves consisting of 7 to 13 leaflets, each of which is wedge-shaped at the base, tapering to a sharp point. The edges of the leaves are wavy-edged (undulate), and the undersides are either hairless (glabrous) or have down-like hair (pubescent). The leaves have red stems that are key to identifying the plant. Fall color ranges from yellow to orange to red.

New bark for a poison sumac tree is a lightish gray that darkens as it ages. The greenish flowers grow in loose clusters about 3 to 8 inches long, leading to gray or creamy white flattened fruits that are about 1/4 inch across.

How to Grow Poison Sumac?

In word: Don't!

Instead, the goal should be to eliminate this toxic plant and avoid it wherever you see it in the wild. The question of how to get rid of poison sumac must be addressed on two separate levels: removal of the plants and treatment for the rash.

Ortho's Brush-B-Gone is recommended for the removal of these woody plants. This product is an herbicidal spray that is available at a variety of home improvement stores. Wear protective gear when spraying to protect yourself both from the poison sumac plants and from the spray.

Light

Poison sumac favors swampy areas with full sun to part shade.

Soil

This plant is normally found in boggy soil with high clay content.

Water

Poison sumac thrives in moist conditions, even with its roots in water.

Temperature and Humidity

This poisonous shrub tolerates a wide range of temperature conditions, but it prefers humid, moist conditions. It is rarely found in arid climates.

Toxicity of Poison Sumac

All parts of this plant are toxic, containing an oily resin called urushiol that causes skin and mucous membrane irritation. This is the same toxin found in poison ivy and poison oak, but it is present in a more concentrated form in this very toxic plant. Contact with skin can cause painful blisters, and breathing smoke from burning poison sumac has been known to cause death. Instead, bag up the branches and send to a landfill or composting center.

Medically, treating the blisters and other rash-related symptoms caused by these poisonous plants is similar to treating poison ivy. According to Marilyn J. Dwelley (Trees and Shrubs of New England) the rash you can receive from this plant is worse than the rash for which poison ivy is infamous.

Comparison With Staghorn Sumac

Poison sumac bears a striking similarity to other types of sumac, especially staghorn sumac (Rhus hirta), an entirely harmless form frequently used in landscape applications. But in poison sumac, the clusters of grayish white berries hang down, and the plants are found in low, wet, or flooded areas, not dry hillsides and meadow edges where other sumacs flourish. Staghorn sumac leaves also have saw-toothed edges, while those of poison sumac are smooth and undulating along the edges.