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Larimer County Weed District

Identification and Management
of Russian olive
(Elaeagnus angustifolia)

Russian olive is most distinctly identified by its silverish leaves. This shrub can grow to over 25 feet tall and has woody thorns and reddish-brown bark.

Russian olive is an exotic shrub that invades riparian areas. In Larimer County, this species can displace native willows and cottonwoods. The effects of this displacement include a loss of both native plant and animal species. For example, blue herons are dependent on upon cottonwood habitat for nesting.

According to Laurie Deiter, City of Boulder Open Space, control is difficult once trees are mature. Ideally, control should occur before fruiting to prevent the spread of seeds. Trees smaller than 4 inches in diameter should be pulled out with a weed-pulling tool when the ground is moist. More mature trees should be cut down to the ground level and an appropriate herbicide should be applied. Herbicides that contain glyphosate, such as Rattler or AquaNeat (for aquatic areas), and triclopyr such as Pathfinder II, should be applied to the cut surface. Also, girdling, stump burning, and depositing rock salt inside holes drilled into the stump may have limited success.

The picture above depicts Russian olives at Boyd Lake State Park in Loveland. Although this shrub is an invader of riparian areas, it does tolerate drought and poor soils. For this reason, many Russian olive trees were planted as shelterbelts or as landscaping trees in the arid West. It has escaped cultivation and continues to spread.

The picture below shows Russian olive seeds. These seeds are hard and olive-shaped. In late spring, small clusters of aromatic, yellow flowers appear.

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