Russian olive and its relatives, autumn olive and thorny olive, are shrubs, subshrubs and small trees that are considered invasive plants in Chicago, Illinois and throughout the U.S. Once considered the solution to the windblown, barren plains states, this almost indestructible plant adapted so well that it is now a threat to native species. http://www.invasivespeciesinfo.gov
Native to Russia, Asia Minor, China and India, Russian olive was first cultivated in Germany in the 1700s. Europeans in southern and central Europe used it as an ornamental plant because it was drought resistant, produced scented flowers, bore unripe yellow and ripe red fruits and possessed black bark. It was introduced in North America in the late 1800s.
Russian olive grows to a mature height of 35-40 feet in three years. It’s a dense, erect shrub, subshrub or small tree, containing two inch thorns. It has silvery, crusty branches and silvery gray willow-like leaves, 1-3 inches long. The bark is unevenly stiff and furrowed. Fragrant flowers appear in summer in groups of three. Edible, global fruits are yellow when they are young and turn cherry-red when ripe. Propagation occurs by root crown shoots and suckers, bird and small animal ingestion, and seed transmission.
This aggressive plant is considered invasive because it’s resistant to bio-controls. It grows well in any soil from sandy to heavy clay. It’s fire resistant and can withstand temperatures from -50° to 115°F. It tolerates shade so it can withstand competition from other shrubs and trees. It grows in arid regions, open fields, marshes, riverbanks and streams. It blocks irrigation ditches. It drains the moisture from the ecosystem.
Instead of growing this plant, Chicago gardeners could grow any of these alternatives: bottlebrush buckeye, black chokeberry or American filbert. These alternatives are attractive, native plants that won’t take over a garden. http://www.bestplants.org