Russian olive trees (Elaeagnus angustifolia) are generally not considered poisonous to humans. Severe poisoning from ingesting parts of this tree is not commonly reported. Native to Europe and Asia, this species is widely distributed, and its components are not typically associated with adverse health effects when consumed by people.
Understanding Russian Olive Toxicity
The Russian olive tree, including its fruit, leaves, and bark, is considered non-toxic to humans. The fruit is safe for consumption; when fully ripe, it is edible raw, although it can have an astringent taste if picked too early. The fruit typically has a somewhat dry and mealy texture.
The small seed contained within the fruit is also edible, though its fibrous casing is often discarded. Beyond direct consumption, the fruit can be processed into jellies or sherbets. Research indicates that Russian olive fruit contains beneficial compounds, including flavonoids and various vitamins. Notably, the fruit boasts a high concentration of lycopene, a beneficial antioxidant. There have been reports of infections from thorn punctures, but these are typically bacterial and not due to inherent toxins from the tree itself.
Identifying Russian Olive Trees
The Russian olive tree is a deciduous shrub or small tree, usually growing 10 to 25 feet tall, though some specimens can reach up to 40 feet. Its narrow, lance-shaped leaves are a distinguishing feature, typically ranging from 1 to 4 inches long. These leaves have a unique silvery-green or gray-green appearance on both sides, due to a covering of fine, silvery scales.
The bark of the Russian olive is grayish-brown, thin, and tends to shed in narrow, fibrous strips as the tree matures. Many branches are equipped with sharp thorns, typically 1 to 2 inches in length. Small, fragrant, bell-shaped flowers emerge in clusters of one to three from the leaf axils in late spring to early summer. These flowers are yellowish inside and silvery on the outside. The fruit is olive-like in shape, about 0.5 inches in diameter, and transitions from silvery when immature to tan or brown as it ripens.
Beyond Toxicity: Other Considerations
While not toxic to humans, Russian olive trees present other important considerations, particularly regarding their environmental impact. Introduced to North America in the early 1900s for various purposes like landscaping and windbreaks, the species has readily spread beyond cultivation. It is now recognized as an invasive species in many regions, especially in riparian zones. This tree can outcompete native plant species, forming dense stands that reduce biodiversity.
The tree’s ability to alter soil chemistry is an ecological concern. It can fix atmospheric nitrogen in its roots, leading to increased nitrogen levels in the soil. This change in nutrient availability can disadvantage native plants not adapted to such conditions. The dense canopy created by Russian olive can also prevent native seeds from germinating due to reduced light penetration. Beyond environmental concerns, Russian olive pollen contains a protein that can trigger allergic reactions in sensitive individuals. Symptoms may include sneezing, a runny nose, itchy or watery eyes, coughing, and sometimes wheezing or hives. This allergic response is a reaction to the airborne pollen, distinct from any effects of ingesting the plant.