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, grows up to 9 m
- Silvery-green leaves
- 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 autumn olive (Elaeagnus umbellata). Russian olive can be distinguished from autumn olive by its leaves, which are more lance-shaped and long (4-9 cm long and 1-2.5 cm wide). Additionally, Russian olive fruits are more silver-yellow-brown, whereas autumn olive fruits ripen to red or pink when mature.
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 soil is moist
- Once seedlings become firmly established, extract with an excavator or backhoe in the winter; all resprouts must be continually cut and removed throughout the growing season; this approach is more effective when followed up with chemical control
- Mowing will not kill Russian olive trees but can suppress saplings that have a stem of less than 2.5 cm in diameter
- 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), and is currently being researched in North America; studies have revealed significant reductions in fruit set, which will likely translate to a reduction in long-distance dispersal in the invaded range
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.
