Russian olive is a small tree with low branches and a trunk that often leans; easily recognized by its silvery leaves.
Leaves are simple, alternate, narrow, 2–3½ inches long, lacking teeth, tip somewhat pointed; upper surface dull gray-green, sometimes with silvery scales; lower surface covered with silvery white scales.
Bark is thin, dark gray to brown, with shallow grooves, ridges flat, shedding in long strips.
Twigs are slender, reddish, coated with gray, scaly hairs, later becoming smooth; twigs often with short spines.
Flowers May–July, scattered on the branches in leaf axils, in clusters of 1–3 flowers; flowers small, up to ¼ inch long, silvery yellow, fragrant, petals absent.
Fruit August–October, oval, about ½ inch long, yellow to tan but densely covered with silvery scales; flesh yellow, waxy, mealy, sweet, with a single stony pit.
Height: to 25 feet.
Has been planted, and often escapes, statewide. A native of southern Europe and western Asia to the Himalayas, it has become naturalized to the point of invasiveness in the central and western states. In states to our east, it rarely escapes from cultivation.
Habitat and Conservation
Planted in yards, it escapes into disturbed sites and idle ground where it spreads by seed or by root sprouts, often forming thickets. In the past, many state and federal agencies encouraged its planting in the Great Plains and West to provide wildlife cover and food and for windbreaks. However, it proved to be invasive, outcompeting native plants and disrupting ecosystems. It is not recommended for planting, since it may become invasive in our state, too.
Although not yet a serious threat in Missouri, it may eventually become invasive like its relative autumn olive (E. umbellata). Russian olive can fix nitrogen in its roots and grow on infertile soils; it can come to dominate streamside vegetation. Although birds eat its fruits, bird diversity actually decreases in areas dominated by Russian olive instead of by the former blend of native species. In many areas it is a nuisance weed, and it could become much worse. It should not be planted.
For a number of reasons, not least of which is its potential for weedy invasiveness, the planting of Russian olive is no longer recommended. Think about what you want (fruits, windbreaks, interesting foliage), and consider planting native hollies, viburnums, hawthorns, or others.
As with many other weedy or invasive plants (like autumn olive, Japanese honeysuckle, and white mulberry), many types of birds eat the fruits and disperse the seeds. Though on one hand it is nice to feed wildlife, in these cases, the net result is negative, as the invasive plants elbow out our native ones.
Taxonomically, Russian olive and autumn olive are not true olives. True olives are in genus Olea, in the olive family (Oleaceae). European olive (Olea europaea) is the species that produces the well-known edible fruits and olive oil; it is grown as an ornamental in warmer climates, but it does not survive Missouri’s winters.