Sumac is a general name for the 250 species of flowering plants in the Rhus genus. It grows in tropical and temperate regions all over the world. Some people may only be familiar with the poisonous variety of sumac that can cause a serious rash much like poison oak and poison ivy do. In fact, most species are harmless shrubs or trees. Some species have medicinal qualities while others are used as a spice in traditional Middle and Near Eastern cuisine.
This plant can potentially become invasive because it propagates itself both by seed and by rhizomes. The shrubs flourish in full sunlight and poor soil, so areas that have been recently cleared for development or farming are particularly at risk for encroaching sumac colonies, which must be removed aggressively. Its relative ease of self-propagation also makes it a good shrub to prevent erosion, as long as its growth is carefully controlled.
Rhus toxicodendron is the species that secretes a poisonous oil, also known as poison sumac. This plant is common in swampy regions of North America, and can be differentiated from other types by its white berries in the fall. Varieties like smooth and staghorn sumac are well-known landscaping trees in temperate regions because of their hardiness and intense autumn colors. The bark, berries, and leaves of most species are edible.
Rhus coriaria is a species of sumac indigenous to the Mediterranean region. Its berries can be dried and pounded to make a spice. Also called sumach, this spice looks like deep purplish-red flakes. It has a sour taste similar to lemon but not quite as astringent. In Greece, Turkey, North Africa, and the Middle East, sumac is used to flavor yogurt for sauces and it can be rubbed on meat and fish prior to grilling. It is also a common seasoning with salads and raw vegetables, and when mixed with sliced onions it gives them a milder, sweeter taste.
The berries of this plant are high in Vitamin C. Native Americans as well as Ancient Greeks and Romans crushed the berries to make a juice like lemonade. It is still widely used in Arabic countries as a fever reducer and to relieve stomach upset. The fruit and bark of some species contain a lot of tannin and can be used to tan hides. Its soft wood is popular with woodworkers and amateur carvers because it is so easy to work with.