Russian olive
Identification & Biology
Photo By: Lisa Scott
Russian olive tree
Russian olive tree
Photo By: Lisa Scott
Russian olive flowers
Russian olive flowers
Photo By: Lisa Scott
Russian olive berries
Russian olive berries
Photo By: Lisa Scott
Young Russian olive
Young Russian olive
Photo By: Lisa Scott
Russian olive tree
Russian olive tree
Photo By: Lisa Scott
Russian olive thorns
Russian olive thorns
Photo By: Lisa Scott
Russian olive in early spring
Russian olive in early spring
Alias' :
Oleaster, Silverberry
Latin Name :
Elaeagnus angustifolia
Category :
Terrestrial Plants
Description :
- Relatively small, deciduous ornamental tree, growing up to 9 m
- Slender, silvery-green leaves with smooth edges
- Fragrant yellow flowers
- Olive-shaped silver berries
- 2.5 – 5 cm thorns grow on reddish-brown branches
- Deep taproot and well-developed root system
Russian olive was first introduced to North America in the late 1800s as a windbreak tree, mostly because of its incredible tolerance of extreme weather. Since then, Russian olive has become a popular ornamental tree known for its attractive silver leaves, fragrant yellow flowers and silver berries. It has become a major problem in the Pacific Northwest and is considered highly invasive. Russian olive blooms in June to July. It produces berries during August to October, which are readily eaten by many species of birds and other wildlife, facilitating the dispersal of seeds. Seeds can remain viable for up to three years in the soil. Russian olive can also grow and spread from stump sprouts, stem cuttings and root pieces.
Russian olive can sometimes be confused with native silverberry/wolf-willow (Elaeagnus commutata). The main difference between these two species is that silverberry is significantly smaller than Russian olive, growing between 2-4 m tall. Silverberry is thornless whereas Russian olive has thorns up to 5 cm long on the stems. Russian olive leaves are more lance-shaped and longer while silverberry leaves are rounder, have wavy edges and are often tinged with a rusty orange colour.
Look Alikes
Photo By: Kumpula Botanic Garden
Silverberry full plant
Silverberry full plant
Photo By: Matt Lavin
Silverberry leaves
Silverberry leaves
Habitat
Native to Europe and western Asia, Russian olive will grow in a variety of soil and moisture conditions. It can tolerate extreme temperatures and low humidity and drought. Russian olive generally prefers sandy floodplains and is often associated with open, moist riparian habitats. In BC this invasive tree is widespread in the Southern Interior, particularly in the Okanagan, and also occurs in the Lower Mainland.
Impact & Risks
- Invades riparian woodlands and crowds out native vegetation
- Threatens large, hardy native trees such as cottonwoods
- Can form dense stands that alter vegetation structure, nutrient cycling and the hydrology of a system
Prevention & Mitigation
- Do not purchase, trade or grow Russian olive
- Regularly patrol your property for invasive trees and immediately control or remove new seedlings
- Cooperate with adjacent landowners and encourage them to prevent invasive tree spread
- Immediately re-vegetate disturbed, bare soils with a suitable seed mixture that provides dense, early colonization to prevent invasion
- Do not move contaminated soils to a new area
Treatment & Disposal
- Seedlings can be hand-pulled or dug out when the soils are moist
- Young trees (trunk diameter 8 cm or less) can be pulled out using a tree wrench; ensure the entire root is removed
- Mowing and brush-cutting can suppress trees, but are only effective if re-sprouts are continually cut throughout the growing season for multiple consecutive years; re-sprouts can be treated with herbicide
- Girdling can help to provide control; in the spring when trees are actively growing, manually cut away bark and cambial tissues around the trunk as close to the ground as possible using an axe
- Cut down large trees, ideally before seeds mature, and apply herbicides to the stump to prevent re-growth; re-cut sprouts and apply herbicide each growing season
- Deep stump grinding (at least 12” deep) is an effective control method. Ensure the entire stump and immediate root system are destroyed
- Chipping is an effective means of disposal for limbs and trunks
- Chemical control is also an option; before applying herbicides, read the label for full use and precautionary instructions
- For further information on the selection and application of chemicals to protect your crop, contact AgriService BC at 1-888-221-7141 or email AgriServiceBC@gov.bc.ca
- A mite has been identified as a promising biological control agent (natural insect enemy) for Russian olive and is currently being researched in North America; studies have found significant reductions in fruit set, which will likely translate to a reduction in long-distance dispersal
For additional information on invasive trees of the Okanagan-Similkameen, check out this factsheet which provides identification, biology, and best management tips: Invasive Tree Factsheet
Okanagan Distribution
Priority Level Definitions
Watch For - Poses a significant threat (very high risk) and does NOT presently occur in the region OR is relatively new to the region and is very limited in extent.
High - High risk/impact; limited population with significant potential to spread in the region.
Medium - Medium risk/impact; limited distribution – broader population distribution with potential to spread further in a region.
Low - Low risk/impact; may be widespread or not, may be of concern in specific situations with certain high values – e.g. specific agriculture crops. Some species may be treated primarily with biological control agents.
