How to Identify Russian Olive (Elaeagnus angustifolia)
This is Russian Olive, a weedy tree species in the Oleaster family. It is native to Europe and central Asia, and is a deciduous perennial that flowers in spring and early summer.

The plant has a thick, woody branched stem that takes the form of a large shrub or tree that can grow 20 to 30 feet tall. The main trunk has gray bark that peels away from the trunk in long strips. The younger twigs have smooth, reddish brown bark, and new growth is green and covered in fine, silvery scales. The branches have sharp thorns that can grow 1 to 2 inches long.

The leaves are oblong or lance-shaped, and are covered in tiny, grey scales that give the leaves a silvery hue. These scales are present of the leaves, petiole, buds, stems, and fruits of the tree.

From the leaf axils the tree will produce clusters of tiny yellow flowers. These give off a strong and distinctly sweet odor. They will produce small, silvery-gray olive-shaped fruits that will mature to a pale-yellow color by the end of the season.

The tree has massive lateral roots that can penetrate up to 35 feet deep into the soil.

Russian Olive likes full sun and moist soils, and is a common weed in waterways, meadows, and pastures. It is commonly cultivated as a shade or ornamental tree, but its bird-dispersed seeds and rapid growth rate allow it to escape and colonize natural areas, outcompeting native trees such as cottonwoods. It can quickly drain water reserves, and fixes large amounts of nitrogen into the soil. Due to its large size, extensive root system, and regenerative capabilities, it is very difficult to remove once established.

The fruits of this tree are edible, and are eaten by many different birds, allowing the seeds to be spread over wide areas.

Russian Olive may be confused for Autumn Olive, a closely related species, but is far more common in the Western US, while Autumn Olive is more common in the East. Autumn Olive has broader leaves which lack scales on their upper surface, and has larger, juicy red berries.


Image credit: University of New Hampshire Extension
https://extension.unh.edu/blog/invasi...


Sources:

Weeds of the West, 5th Edition (1991) by Tom D. Whitson, published by the Western Society of Weed Science

University of California Agriculture and Natural Resources IPM – Weed Gallery
http://ipm.ucanr.edu/

United States Department of Agriculture – Plant Database
https://plants.usda.gov