Thursday, May 2, 2013
Autumn Olive: Good Intentions Gone Bad
Autumn olive is an introduced species that was and still is widely planted with good intentions without the foresight of the consequent problems. This mistake has resulted in an invasive species to the eastern United States that is very hard to control. Autumn olive has become invasive from Maine south to South Carolina west to Oklahoma, and north to southwest Minnesota. Autumn olive is native to China, Japan, and Korea and was originally introduced to North America in 1830.
Autumn olive, Elaeagnus umbellate, is a medium to large deciduous shrub. Its leaves alternate along the stem, are oval to lanceolate with smooth edges, and grow to 1-3 inches in length. The upper surface of the leaves is dark green to grayish-green in color, while the lower surface is silvery white. The small, round, juicy, editable fruits are reddish to pink and produced in great quantity.
It exhibits prolific fruiting and aggressive growth which helps it to out-compete and displace native plant species. It is widely disseminated by birds though its seeds do not provide them with the proper nutrition. Autumn olive, like soybeans, can improve soil by adding nitrogen, although it is not in the legume family. This can adversely affect the nitrogen cycle of native communities that may depend on low nitrogen soils. It is drought-tolerable and will tolerate low pH soils often found in southern Ohio. These characteristics help it survive on reclaimed strip mine land or even bare mineral substrates.
Autumn olive invades grasslands and pastures, open areas, and disturbed areas. It does not grow well in wet areas or under the shade of an established forest. It can germinate in thickly matted grasslands and thrive even though it has severe competition.
Autumn olive is dispersed mainly by birds and mammals dropping the seeds. Each plant produces 20,000 to 54,000 seeds per year. It can also reproduce through the roots by root clones. Due to this it can regenerate after a fire or cutting; even coming back thicker than before.
Due to the large available seed bank Autumn olive is becoming a problem in pasture fields. It is one of several invasive species that the USDA Natural Resources Conservation Service (NRCS) is assisting landowners in controlling. Contact your local NRCS office for further information about this program.
Visit the Appalachian Ohio Weed Control Partnership blog, at www.appalachianohioweeds.org, to learn more about Southeastern Ohio’s non-native invasive species. You can also contact Eric Boyda of the Appalachian Ohio Weed Control Partnership by phone at 740-534-6578 or email at email@example.com
Photo Credit: Leslie Mehrhoff. Author: Alan Rees