Russian olive (Elaeagnus angustifolia)

Synonyms: Elaeagnus orientalis, Elaeagnus hortensis, Elaeagnus angustifolia var. orientalis

Common Names: oleaster, narrow-leaved oleaster, Persian olive, wild olive

Description:

Russian olive (Elaeagnus angustifolia) is a thorny shrub or small tree from southern Europe and Asia. It was brought to North America in the early 1900s as an ornamental and a windbreak tree [2]. Since then it has spread along rivers, streams, and other moist places, where it forms dense stands that crowd out native trees like cottonwood and willow [4]. MISIN tracks it because once it takes hold along a waterway, it is very hard to remove [1].

Habit:

Russian olive grows as a large shrub or small tree, usually 16 to 40 feet tall, often with a short trunk that branches close to the ground [1]. Its narrow, lance-shaped leaves are covered in tiny scales that give them a silvery-gray color on both sides, so a plant can look almost frosted from a distance [2]. The leaves and drooping twigs give it a willow-like look. The branches often carry sharp thorns, so handle it with care [1].

It is easiest to spot in summer, when the silvery foliage stands out against the greener native plants around it. In late fall and winter, look for clusters of dry, yellowish, olive-shaped berries that hang on the bare branches after the leaves drop [3]. In late spring it carries small, very fragrant creamy-yellow flowers [1].

At-a-glance cues:

1. Narrow leaves that are silvery-gray on both the top and bottom [2]
2. Sharp thorns along flexible, often drooping branches [1]
3. Small, fragrant, creamy-yellow flowers in late spring (May?June) [1]
4. Dry, mealy, olive-shaped berries that ripen silvery then turn yellowish-tan [1]

Leaves:

1. Arrangement: alternate (one leaf per node, not paired) [1]
2. Shape: narrow and lance-shaped, 1 to 4 inches (2?10 cm) long and up to about 1.5 inches (4 cm) wide [1]
3. Margin: smooth, with no teeth [3]
4. Surface: covered in tiny scales that make both sides silvery-gray; the upper side is a little greener than the underside [2]
5. Overall look: droops slightly, giving the whole plant a willow-like, frosted appearance [3]

Stems:

1. Habit: woody large shrub or small tree, 16 to 40 feet (5?12 m) tall, often branching within a foot or two of the ground [1]
2. Thorns: flexible branches are frequently armed with stiff, sharp thorns up to about 2 inches long [1]
3. Bark: dark gray-brown and smooth on young stems, becoming fissured and shredding with age [1]
4. Young twigs: coated with the same silvery scales as the leaves, so new growth looks silver-gray [2]

Flowers:

1. Color: creamy-yellow, silvery on the outside [2]
2. Shape: small and bell-shaped, only about a quarter-inch long, and strongly fragrant [1]
3. Arrangement: in small clusters where the leaves meet the twigs [1]
4. Bloom time: late spring, generally May to June [1]
5. Sex: flowers are perfect (each has both male and female parts) and are pollinated by insects [1]

Fruit and seeds:

1. Fruit type: oval, olive-shaped berry about a half-inch (1?2 cm) long, dry and mealy rather than juicy [1]
2. Color & ripening: silvery at first, turning yellowish-tan to orange when ripe in late summer; berries often hang on through fall and winter [1]
3. Seeds: each berry holds a single hard, stony seed [1]
4. Dispersal: birds eat the berries and drop the seeds far from the parent plant; berries also float and travel downstream on the water for up to two days [1]

Habitat:

Russian olive is native to southern Europe, western and central Asia, and the Middle East, and was introduced to North America in the early 1900s [1][2]. It does best in moist ground and is most aggressive along riverbanks, streambanks, lakeshores, floodplains, wet meadows, and irrigation ditches. It also turns up in fields, fence lines, and along roadsides [1].

It prefers full sun but tolerates some shade, which lets young plants wait in the understory until an opening appears [4]. It is unusually tough: its roots partner with soil bacteria to pull nitrogen from the air, so it thrives in poor, salty, and alkaline soils where many native trees cannot [2]. It handles drought, and survives temperatures from about ?50 ?F to 115 ?F (?45 ?C to 46 ?C), growing from sea level up to around 8,000 feet [1].

Reproduction:

Russian olive spreads mainly by seed. Birds eat the berries and drop the seeds wherever they land, which is how new plants show up far from any parent tree ? often along a fence line or stream where birds perch [3]. Berries that fall into water float downstream and start new plants on fresh banks [1]. A single tree can produce a heavy crop of fruit, and the seeds can stay alive in the soil for up to three years [3]. Seeds need a cold winter before they will sprout in spring [1].

Plants usually begin producing fruit between about 3 and 10 years old [1]. The plant also resprouts strongly: if you cut, mow, or burn it, it sends up new shoots from the stump, root crown, and roots [1]. Because of this, the best time to act is early ? pull young seedlings in spring when the soil is moist, and remove plants before the berries ripen in late summer to stop new seeds from spreading [1].

Impact and Damage:

For a homeowner, the most immediate problem is the thorns. Russian olive forms dense, thorny thickets that are hard to walk through and can block access to a shoreline or path, and the stiff thorns can injure people and pets [1]. The berries are not poisonous ? people and wildlife eat them ? so it is not a poisoning risk to children or pets [1]. Its biggest property impact is crowding: it shades out garden plants, lawn edges, and native shrubs, especially in damp areas [4].

In natural areas, the damage runs deeper. Along rivers and streams it forms dense stands that shade out and replace native cottonwoods and willows; native tree seedlings rarely survive under its canopy [4]. Its nitrogen-fixing roots change the soil, raising nitrogen levels in ways that can favor other weeds over native plants [5]. Because it taps groundwater with deep roots, large stands can draw down water in dry regions [4]. Stands of Russian olive also support fewer of the insects that native riparian forests provide for nesting birds, so they offer poorer wildlife habitat overall despite the bird-eaten berries [4]. Clearing it from western waterways is costly and often takes repeated effort over several years [4].

Similar species:

Several silvery-leaved shrubs are mistaken for Russian olive. None of MISIN's tracked look-alikes were on file for this species, so the comparisons below come from published references.

Autumn olive (Elaeagnus umbellata) is the closest match and also invasive. It stays more of a spreading shrub, and its broader oval leaves are green on top with a silvery underside ? not silvery on both sides like Russian olive. Its berries are juicy and red with silver speckles, while Russian olive's are dry and yellowish [3][6].

Silverberry (Elaeagnus commutata) is a native shrub with silvery leaves on both sides, much like Russian olive. Tell them apart by size and thorns: silverberry is a smaller, thornless shrub that spreads by underground runners, and its flowers are a deeper yellow [6].

Silver buffaloberry (Shepherdia argentea) is a native thorny shrub with silvery foliage, so it is easy to confuse at a glance. The giveaway is the leaves: silver buffaloberry has paired (opposite) leaves, while Russian olive's are single and alternate. Its berries are also bright red and juicy [6].

Russet buffaloberry (Shepherdia canadensis) is another native look-alike with paired (opposite) leaves and no thorns. Its leaves are green on top with rusty-brown scales underneath, rather than uniformly silver, and its small berries are red [6].

Monitoring and rapid response:

Signs to watch for:

1. Silvery, willow-like foliage standing out along streambanks, shorelines, and field edges ? easiest to spot in summer [3]
2. Dry, yellowish, olive-shaped berries hanging on bare branches in fall and winter [3]
3. New seedlings popping up along fence lines and stream edges where birds perch [1]

What you can do:

1. Hand-pull or dig out seedlings and young plants when the soil is moist in spring, removing the whole root [1]
2. Bag and dispose of any berries so they cannot sprout or be carried off [3]
3. Remove plants before the berries ripen in late summer to stop new seeds from spreading [1]
4. Remember that simply cutting or mowing makes it resprout, so cutting alone is only a first step [1]
5. For a natural area crew: target isolated outlier plants and seed-producing trees first to slow the spread, and plan to revisit the site for several years because resprouts and buried seed keep coming back [4]

When to call a professional:

1. Large or mature trees and dense thorny thickets that are unsafe or impractical to remove by hand [1]
2. Plants that keep resprouting aggressively from the stump and roots after removal [1]
3. Infestations on streambanks or other riparian areas, where cut-stump work and erosion need expert handling [4]
4. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Zouhar K (2005). Elaeagnus angustifolia. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. research.fs.usda.gov/feis
2. USDA NRCS Plant Guide. Russian olive (Elaeagnus angustifolia L.). USDA NRCS Plants Database. plants.usda.gov
3. Minnesota Department of Natural Resources. Russian olive (Elaeagnus angustifolia). dnr.state.mn.us
4. Katz GL, Shafroth PB (2003). "Biology, ecology and management of Elaeagnus angustifolia L. (Russian olive) in western North America." Wetlands 23(4):763?777. semanticscholar.org
5. DeCant JP (2008). "Russian olive, Elaeagnus angustifolia, alters patterns in soil nitrogen pools along the Rio Grande River, New Mexico, USA." Wetlands 28(3):896?904. semanticscholar.org
6. Penn State Extension. Invasive Autumn and Russian Olives. extension.psu.edu

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