Eagle County weed of the week: Russian olive
Vail, CO Colorado
Originally planted for agricultural windbreaks and as a landscape ornamental, this escaped European and Western Asian native invades riparian corridors, driving out native alders, cottonwoods and willows. This plant can be found in gardens, home and commercial landscapes and native areas throughout Eagle County and is targeted by Eagle County’s municipal and county Noxious Weed Management Programs.
• Shrub or small tree that grows between 10 and 40 feet tall.
• Easily recognized by the silvery, scaly underside of the leaves and slightly thorny stems.
• Leaves are gray-green in color, lance-shaped and 1 to 3 inches long.
• Stems can be reddish brown in color.
• Fruit resembles olives.
• Extensive, suckering root system forms dense colonies.
• Consumes water at a higher rate than native trees.
• Control of this species can be difficult. However, young plants are most easily controlled.
• The girdling method has been shown to be effective. This involves making shallow, overlapping cuts into the bark around the trunk base using a hatchet or chain saw and then lightly spraying the entire cut surface with herbicide. A small, finger-trigger spray bottle is usually adequate for these applications.
• Some applications have experienced more success in the fall when the trees are moving reserves to their roots.
• Cutting, immediately followed by brushing stumps with triclopyr (Garlon 4), has been shown to be an effective method for control of this invader.
• Fire, in combination with herbicide spraying of stumps, can prevent Russian olive from sprouting from the root crown.
• If you have this plant in your home landscape, remove it as soon as is practical. There are numerous replacement options.
• Substitutes include a variety of hawthorns (Crataegus species), the native mountain ash (Sorbus scopulina), silver buffaloberry (Sheperdia argentea) and numerous species of crabapple (Malus species).
For more information on these plants and the Noxious Weed Management Programs in Eagle County, visit http://www.eaglecounty.us/weed or http://www.vailgov.com/weeds or call the Eagle County Weed and Pest Department at 970-328-3540, the town of Vail Department of Public Works at 970-479-2158 or the Eagle County Extension Office at 970-328-8630.