By Celestine Duncan
Autumn olive (Elaeagnus umbellata) and Russian olive (Elaeagnus angustifolia) are invasive, deciduous, woody shrubs or small trees that were introduced for landscaping, soil stabilization, and wildlife food/cover. Both plants became invasive in riparian areas, open forests, lake shores, and abandoned fields. Although the plants share similar habitat, autumn olive is more widespread in the eastern half of the United States, and Russian olive is more prevalent in the West (Figure 1).
Autumn olive is native to China, Japan, and Korea and was introduced to the United States in the 1830s. Russian olive is native to southern Europe and western Asia and was introduced into North America as an ornamental in the early 1900s. In the United States, both plants were actively promoted for wildlife habitat and erosion control in environmentally disturbed areas. Russian olive was also planted extensively in windbreaks in the western U.S. These woody plants spread long distance by birds that ingest seed, or locally by small mammals that gather and stockpile seeds. The two plants share similar growth form and habitat, but differ in leaf shape and size, and berry color. Following are diagnostic characteristics that differentiate the two species.
Autumn olive (top left): Leaves are elliptical to egg-shaped; 2 to 4 inches long and ½ to 1¼ inches wide; dark green to grayish green on upper surface with dense, silvery scales on the underside. Leaves are arranged alternately along stems and have un-toothed, wavy margins. Photo, Mark Renz, University of Wisconsin.
Russian olive (bottom left): Leaves are lance-shaped or oblong; 1½ to 3¼ inches long and 3/8 to ¾ inch wide; dull gray-green above with dense, silvery scales coating both sides. Leaves are arranged alternately along stems and have un-toothed, wavy margins.
Photo, Celestine Duncan.
Both plants have thorns, with short spines at tips (more typical of Russian olive).
Autumn olive (top left):Young stems have brown to orange scales. Photo, James H. Miller, USDA Forest Service.
Russian olive (bottom left): Young stems have silvery scales. Photo, Celestine Duncan.
Flowers of both species are bisexual with similar shape and size.
Autumn olive (top left): Conspicuous clusters along twigs at the base of leaves, appearing early spring to early summer. Creamy-colored to light yellow with silvery exterior; bell-shaped and aromatically fragrant; 0.3 to 0.4 inch wide. Photo, The Nature Conservancy
Russian olive (bottom left): Flowers are produced in umbel-like inflorescences from the leaf axils and are fragrant; 0.4-0.5 inch wide. Plants are capable of flowering and setting fruit in three years, usually blooming in late May and early June. Photo, Patrick Breen, Oregon State University, Bugwood.org
Autumn olive (top left): Fruit are ¼ inch silvery, juicy berries dotted with brown scales that ripen to red or pink when mature in fall. Single-seeded fruit are borne on short stalks. Photo, Pennsylvania Department of Conservation and Natural Resources, Bugwood.org.
Russian olive (bottom left): Fruit are 3/8 to ½ inch long; elliptical, dry, mealy yellow-brown berries with silvery scales that become shiny when mature in late summer and fall. Fruits persist throughout the winter. Seeds remain viable in the soil for approximately three years. Photo, Celestine Duncan.