Many people associate the name “sumac” with toxicity, often confusing it with rash-inducing plants. However, Rhus glabra, or smooth sumac, is a native North American species that is not poisonous to humans. It does not cause the blistering skin reactions linked to its relatives.
Understanding Smooth Sumac
Smooth sumac is a deciduous shrub or small tree, typically growing between 9 to 15 feet tall. Its leaves are pinnately compound with 11 to 31 individual leaflets along a central stem. These leaflets have finely toothed edges and turn a vibrant scarlet in the fall.
During late summer and fall, smooth sumac produces distinctive red, conical fruit clusters, known as drupes, which often persist throughout winter. These upright clusters are a key visual cue for identification. The plant thrives in disturbed areas, open woodlands, prairies, and along roadsides. Smooth sumac does not contain urushiol, the oily resin responsible for skin irritation caused by some other plants.
Identifying Smooth Sumac and Its Look-Alikes
Smooth sumac has stems that are notably smooth and hairless. Its bright red berry clusters grow upright at the ends of branches, and its leaves feature many serrated leaflets, typically ranging from 11 to 31.
In contrast, poison sumac (Toxicodendron vernix) is a highly allergenic plant that contains urushiol. It prefers very wet, swampy habitats, unlike the drier conditions favored by smooth sumac. Poison sumac has fewer leaflets per stem, usually 7 to 13, and its berries are white or grayish, hanging in loose, drooping clusters. The stems of poison sumac can be reddish, and its leaflets have smooth, untoothed margins.
Poison ivy (Toxicodendron radicans) and poison oak (Toxicodendron pubescens) are also urushiol-containing plants. These plants have “leaves of three,” a distinct difference from the numerous leaflets found on all true sumac species. Poison ivy grows as a vine or low shrub with white or tan fruit, while poison oak appears as a shrub with lobed leaves resembling oak leaves.
Safety and Uses of Smooth Sumac
Smooth sumac is considered safe for human contact and is non-toxic to common household pets. While ingesting large quantities of any plant material can cause mild stomach upset, smooth sumac does not pose a serious poisoning risk. The plant’s red berries are edible and have a tart, lemony flavor due to the presence of malic acid.
These berries are commonly used to make a refreshing beverage known as “sumac-ade” or “Indian lemonade.” To prepare, steep the red berries in cold water for several hours, then strain the liquid to remove the fine hairs. Boiling the berries is generally avoided as it can extract bitter tannins.
Beyond its culinary uses, smooth sumac is valued for its ornamental qualities, particularly its vibrant red fall foliage and persistent red fruit clusters. While smooth sumac is generally harmless, individuals with sensitivities to other members of the cashew family, such as cashews or mangoes, may experience mild skin irritation from direct contact, though this is not related to urushiol.