Autumn olive is a deciduous shrub or small tree in the Oleaster family (Elaeagnaceae) that grows to approximately 20 feet in height. Leaves are dark green, alternate, oval to lanceolatea leaf that is wider at the base than at the midpoint, tapers toward the apex, and has a length-to-width ratio of 3:1 or more, and untoothed. The underside is covered with silver-white scales. The small, light yellow flowers are borne along twigs after the leaves have appeared early in the growing season. The small, round, juicy fruits are reddish to pink, dotted with scales, and produced in great quantities. Birds forage on its fruits and contribute to seed dispersal.
Autumn olive is easily confused with a closely related species, Russian olive, which is also an invasive species. Russian olive has elliptica leaf that is not divided into parts to lanceolatea leaf that is wider at the base than at the midpoint, tapers toward the apex, and has a length-to-width ratio of 3:1 or more leaves, its branches are usually thorny, and its fruit is yellow, dry and mealy.
It grows well in a variety of soils including sandy, loamy, and somewhat clayey textures with a pH range of 4.8-6.5. It has nitrogen-fixing root nodules which allow it to thrive in poor and infertile soils. Mature trees tolerate light shade, but produce more fruits in full sun, and seedlings may be shade intolerant. It does not do well on wet sites or in densely forested areas. It is drought tolerant and may invade grasslands and sparse woodlands. Typical habitats are disturbed areas, roadsides, pastures and fields.
History and Introduction
In the early 19th century, Autumn Olive was purposely introduced to the United States and the United Kingdom for shelter belts, erosion control, wasteland reclamation, wildlife habitat, and for gardens as an ornamental. By the late 20th century, the shrub became a noxious weed and invasive species in many US states from the east coast to the central prairies, and spread widely across Europe.
Autumn olive has the potential of becoming one of the most troublesome shrubs in the central and eastern United States. It out-competes and displaces native plants by creating a dense shade that hinders growth of native vegetation that need sunlight. Autumn olive exhibits prolific fruiting and rapid growth that suppresses native plants. It can produce up to 200,000 seeds in a year. It is widely disseminated by birds and can easily adapt to many sites. Due to its nitrogen-fixing capabilities, it has the capacity to adversely affect the nitrogen cycle of native communities that may depend on infertile soils. Its nitrogen-fixing capabilities also allows them to grow in harsh environments with unfavorable soils. It grows quickly and with comparatively little resources, so they can take over in a short period of time. They germinate easily and even attempts at removing autumn olive may cause unwanted spreading.
Seeds are spread widely by birds, and to a lesser extent by small mammals. Other species known to eat Autumn Olive are raccoons, skunks, opossums, and black bears. It is also browsed by white-tailed deer.
Seedlings and sprouts can be hand-pulled when the soil is moist to insure removal of the root system. Note: On larger plants, cutting alone results in thicker, denser growth. Burning during the dormant season also results in vigorous re-sprouting.
It can be effectively controlled using any of several readily available general use herbicides such as glyphosatea widely used herbicide that can kill certain weeds and grasses, it works by blocking an enzyme essential for plant growth. Foliar application has proven effective in controlling these species. Since glyphosate is a nonselective herbicide it will affect all green vegetation with which it comes into contact. Care should be taken to avoid impacting native plant species. Glyphosate herbicides are recommended because they are biodegradable. Follow label and state requirements.
Autumn Olive Flowers
Japanese Silverberry, Umbellata Oleaster, Autumn Elaeagnus, Spreading Oleaster, Autumn Berry Bush
Eastern Asia and ranges from the Himalayas eastwards to Japan
Russian Olive (Elaeagnus angustifolia), Thorny Olive (Elaeagnus pungens)
Autumn Olive Leaves
Autumn Olive Fruit
Autumn Olive Bush
Image Attributions: Autumn Olive Flowers - Tracy Lee Carroll, Flickr | Autumn Olive Leaves - KENPEI, Wikimedia Commons | Autumn Olive Fruit - Vinayaraj, Wikimedia Commons | Autumn Olive Bush - Amy Stone, The Ohio State University