Smooth Sumac (Rhus glabra)

Family:

Cashew Family (Anacardiaceae)

Other Names:

wild sumac.

Origin and Distribution:

Smooth sumac is a native of eastern U.S. Currently, it has a range extending throughout the U.S. except for an area in North Dakota and Montana. Smooth sumac can be found growing in all 88 counties of Ohio. It establishes on clearings, hillsides, and such disturbed sites as roadsides and reduced-tillage fields. With the exception of bogs, swamps, and shaded areas, smooth sumac tolerates nearly any condition and type of soil.

Plant Description:

This deciduous, woody perennial grows in a colony as a shrub or it may grow alone as a small tree. Smooth sumac has compound leaves composed of many 2- to 4-inch-long leaflets. Leaflets turn bright colors before falling off in the fall. Its stems are branched and smooth. Red fruits, which are covered with minute hairs, form in dense clusters located at the tips of branches. Reproduction is by seeds and rhizomes (horizontal underground stems).

  • Root System:

    Root systems tend to be shallow and wide-spreading.

  • Seedlings and Shoots:

    Young shoots are tan to medium brown and hairless.

  • Stems:

    Plants are usually between 2 to 15 feet tall, although 25-foot-tall trees have been recorded. Stems are generally less than 2 inches wide. Branches may be square in cross-section. Bark is thin, smooth, and brownish-gray. Twigs are hairless and light brown. When cut, stems exude a milky sap. Branches display U-shaped leaf scars in winter.

  • Leaves:

    Leaves are alternate (1 leaf per node) and compound with between 9 to 31 leaflets. Leaves are 8 to 20 inches long. Leaflets are located opposite each other with a single leaflet located at the tip of each leaf. Leaflets are 2 to 4 inches long, shaped like oblong lances, and have coarsely-toothed edges. In summer, leaflets are dark green above and much paler below. In fall, they turn a range of colors from orange to scarlet to purple before falling off. Leaves attach to stems by way of hairless stalks (petioles

  • Flowers:

    Small greenish-yellow flowers form 3- to 5-inch long, pyramid-shaped clusters located at the end of stems. Male and female flowers are located on separate trees.

  • Fruits and Seeds:

    Fruits are bright red with dense but short, minute hairs.

Similar Species:

Dwarf sumac (Rhus copallina) is similar in appearance except its stems have raised dots and its leaflets have smooth edges. Staghorn sumac (Rhus typhina) is distinguished from smooth sumac by the long hairs covering its stems, petioles, and fruits. Staghorn sumac fruits are in more erect clusters than those of smooth sumac. Naturally occurring crosses between staghorn and smooth sumac result in hybrid offspring with such intermediate characteristics as medium-long hairs on twigs and fruit. Characteristics of poison sumac (Toxicodendron vernix), which causes dermatitis in sensitive individuals, distinguishing it from smooth sumac are white hairless fruits and smooth-edged leaves. Leaves of tree-of-heaven (Ailanthus altissima) are also compound but their leaflets have 1 to 2 teeth located near the base compared to smooth sumac leaflets that have numerous teeth all around the edge.

Biology:

Flowering begins in June and continues through July. Because plants spread by rhizomes, an area can become populated by many related plants with overlapping crowns that give the appearance of a dense colony with an extensive rounded or flat top.

Toxicity:

None known. However, the cashew family also includes poison ivy, poison oak, and poison sumac. Persons sensitive to these other plants should be cautious around staghorn sumac.

Facts and Folklore:

  • Native Americans used sumac as an antiseptic and astringent and in place of tobacco.