Russian Olive (RO) (Eleagnus angustifolia) is a highly invasive species that has moved rapidly into the Escalante River watershed in the past 25‐30 years. Deliberately introduced into many states during the 1930’s Dust Bowl era to address soil erosion, the Russian Olive is particularly destructive to desert riparian corridors. The RO consumes large amounts of water thereby reducing stream flow, chokes out native plant species, such as willow and cottonwood, and has dense root systems that destructively channel heavy stream flows. And, adding injury to insult (sorry!), the RO produces 2-4-inch, strong thorns that can damage equipment, lame animals, and wound people.
Identifying Russian Olive- RO is a fast-growing tree that can reach up to 25-30 feet and form dense thickets of several trees growing close together. The branches are dark reddish brown and have sharp thorns. The leaves are green/gray on the top and silver/gray on the bottom. Both leaves and branches grow in an alternate pattern. The olive (fruit) is silver to brown.
Tamarisk sp. – TAsp.
Tamaricaceae (Tamarisk Family)
Tamarisk can be found throughout the Escalante River drainage. Described as a shrub or small tree growing to around 8 ft (although highly variable) with multiple shoots emerging from a central root system with rough, reddish-brown bark. Branches are thin, dense, springy, and whip-like. Leaves are small, scale-like, green, and often overlapping in a shingle-like pattern. Flowers emerge on spike- or horn-shaped racemes and are purple when blooming and dull yellow when dead. Tamarisk species are invasive throughout the country, targeting sandy drainage banks and floodplains where they grow very densely, crowd out native vegetation, channelize banks, and accumulate sediment.
Centaurea repens – CERE
Asteracea (Sunflower Family)
Russian knapweed is a primary noxious weed in many areas of the U. S. including Utah. It is mainly confined to flood plains, roadsides, and other disturbed areas that are at least seasonally moist. This species has not been found along the Escalante River, it does however occur in watersheds that surround the Escalante. If this species is detected along the Escalante River managers need to be made aware of this.
USDA Utah Noxious Weeds (PDF)