Identifying Bastard Oleaster
Bastard oleaster, commonly known as autumn olive (Elaeagnus umbellata), is a deciduous shrub or small tree. It typically grows 10 to 20 feet tall, sometimes reaching 30 feet, with a multi-stemmed, sprawling habit and thorny branches. Its distinctive features include unique foliage, small, aromatic flowers, and abundant fruit.
The leaves are alternate, oval to lance-shaped, 1 to 3 inches long. Their upper surface is dull green, while the underside is densely covered with silvery-white scales, creating a shimmering, two-toned appearance. This silvery underside is a key identification feature.
In spring, from April to June, autumn olive produces numerous small, pale yellow, trumpet-shaped, fragrant flowers in clusters. After blooming, it develops abundant small, round, berry-like fruits, about 0.25 to 0.35 inches in diameter.
These fruits ripen from late summer through fall, turning reddish-brown and often speckled with silvery scales. Young stems have smooth, grayish-brown bark, which becomes more fissured with age. Key identification points are the silvery undersides of the leaves and the speckled red fruits.
Ecological Impact
Autumn olive is an aggressive invasive species due to its rapid growth and prolific seed production. It quickly establishes in disturbed areas, open fields, and forest edges, outcompeting native vegetation for sunlight, water, and nutrients. This competitive advantage allows it to form dense monocultures, significantly reducing biodiversity.
Its invasiveness is amplified by its ability to fix atmospheric nitrogen through a symbiotic relationship with soil bacteria. This enriches the soil, altering chemistry and nutrient cycles. Such changes disadvantage native plant species adapted to nutrient-poor soils, further facilitating autumn olive’s dominance.
Dense thickets degrade wildlife habitat by displacing native food sources and shelter. While its fruits are consumed by birds and mammals, leading to widespread seed dispersal, the plant does not support the same diversity of insects and organisms as native vegetation. This contributes to a decline in ecosystem health.
The proliferation of autumn olive also has economic implications. Its management and removal from agricultural lands, natural areas, and rights-of-way require substantial resources. The costs for control and habitat restoration are considerable, making it challenging to contain once established.
Managing and Controlling Bastard Oleaster
Effective management of autumn olive requires a combination of methods, often called Integrated Pest Management (IPM). Prevention is a primary step, involving avoiding its planting and restoring native plant communities. Early detection and rapid response to new infestations are crucial.
For small, young plants, manual removal is effective, especially when soil is moist, ensuring the entire root system is extracted. Larger plants or dense thickets often require mechanical methods, such as cutting stems close to the ground.
Mechanical cutting often requires follow-up treatment, as autumn olive readily resprouts from cut stumps. Applying a systemic herbicide directly to the cut stump immediately after cutting is a highly effective chemical control method. This “cut-stump” treatment ensures herbicide translocation throughout the root system, preventing regrowth.
Foliar spray applications can be used for widespread infestations of smaller plants, but care must be taken to avoid drift. Basal bark treatments, applying an oil-soluble herbicide to the lower 12-18 inches of the stem, are another option for individual plants. Always follow herbicide label instructions regarding application rates, personal protective equipment, and environmental precautions.
After removal, proper disposal of plant material prevents resprouting or further seed dispersal. Currently, no widely available or effective biological control options exist for autumn olive. Combining methods, such as cutting and then treating stumps, offers a robust approach to managing this persistent invasive plant.
Historical Context and Uses
Autumn olive was intentionally introduced to North America from East Asia in the mid-1800s. Its introduction was driven by several perceived benefits, including its rapid growth, ability to thrive in poor soils, and its capacity to stabilize eroding land. It was widely planted for erosion control, as a windbreak, and to provide food and cover for wildlife, particularly birds.
The plant was also promoted for its nitrogen-fixing capabilities, with the idea that it could improve soil fertility in degraded areas. While it does enrich the soil with nitrogen, this often leads to detrimental ecological changes in non-native environments, disrupting the balance of native ecosystems. Its berries are indeed edible, with a tart flavor, and are sometimes used in jellies, jams, or sauces.
Despite these historical uses and the edibility of its fruit, the plant’s aggressive invasive nature far outweighs any perceived benefits. Its ability to spread rapidly and outcompete native flora has led to significant ecological disruption across many landscapes. Consequently, the planting of autumn olive is now widely discouraged, and efforts are focused on its control and removal rather than its cultivation.