SPECIES CHARACTER
Description
Autumn olive is a medium to large shrub, often reaching heights of 20 feet. The
leaves, borne alternately on the stems, are generally oval in shape,
approximately 1-3 inches (2.5-7.5 cm) long, and lack teeth. The upper surface
of leaves is dark green to grayish-green in color, while the lower surface is
covered with silvery white scales, a conspicuous characteristic that can be seen
from a distance. The small light yellow flowers bloom in late April and May
after the first leaves have appeared. Flowers and fruits, when present, are
borne along twigs. The small (less than 1/4 inch) fleshy fruits range in color
from pink to red and are produced in abundance each year.
Similar Species
Autumn olive is distinguished from other shrubs in Illinois by the silvery white
scales covering the lower leaf surface and by its elliptical or ovate leaves that
often have a slightly wavy margin. Autumn olive resembles Russian olive
(Elaeagnus angustifolia), another exotic shrub, in that leaves of both species
appear silvery on the lower surface. However, Russian olive has narrower leaves
that are lanceolate in shape. Autumn olive should be accurately identified
before attempting any control measures. If identification of the species is in
doubt, the plant's identity should be confirmed by a knowledgeable individual
and/or by consulting appropriate books.
Distribution
Autumn olive was introduced into U.S. cultivation in 1830 from its native range
in China, Japan, and Korea. In Japan, this species is common and variable,
occurring in thickets and thin woods in both lowlands and uplands. The species
was studied in the 1940's by the Soil Conservation Service and the strain
'Cardinal' was released in 1963 for commercial propagation. In the eastern and
central United States, autumn olive has been planted primarily to provide food
and cover for wildlife but also as screens and barriers along highways, to
stabilize and revegetate road banks, and to reclaim mine spoil. As late as 1975
this species was described as escaping rarely from cultivation. By 1981, it had
been documented as naturalized in Illinois. Autumn olive has been officially recorded from only 6 counties; it is, however, probably
found in most counties now.
Habitat
Autumn olive occurs in disturbed areas, successional fields, pastures, and
roadsides, where it has been widely planted. It has been noted from prairies,
open woodlands, and forest edges. Autumn olive rarely is encountered in dense
forests or in very wet sites.
Life History
Autumn olive is a non-leguminous, nitrogen-fixing woody shrub. Plants flower
and develop fruits annually after reaching 3 years of age, although 2 year old
plants have been known to flower. An in dividual plant can produce up to 8
pounds of fruit. Seed dispersal appears to be mainly by falling fruit and
birds. Birds seem to be the primary vector for dispersal, although raccoons,
skunks, and opossums are known to feed on the fruit. Once established, this
species is highly invasive and difficult to control. Burned, mowed, or cut
plants will resprout vigorously.
Current Status
Currently, there are no restrictions on the sale or use of autumn olive in
Illinois.
CONTROL RECOMMENDATIONS
RECOMMENDED PRACTICES IN NATURAL COMMUNITIES OF HIGH QUALITY
Young seedlings and sprouts can be handpulled in early spring when adequate
ground moisture is present to allow removal of the root system along with above-
ground growth. Autumn olive is easily seen in early spring because its leaves
appear while most native vegetation is still dormant.
Cutting the plant off at the main stem and applying herbicide to the stump has
been effective in killing root systems and preventing resprouting. Roundup
herbicide (a formulation of glyphosate) has been effective in controlling autumn
olive when used as a 10-20% solution and applied directly to the cut stump.
Although the Roundup label specifies a higher concentration for cut-stump
application (50-100%), this lower concentration has proven effective. Roundup
can be applied either by spraying individual stumps with a low pressure hand-held
sprayer or else by wiping each stump using a sponge applicator (sponge-type paint
applicators can be used). With cut-stump treatment, herbicide is applied
specifically to the target plant, reducing the possibilities of damaging nearby,
desirable vegetation. Cut-stump treatment is particularly effective late in the
growing season (July-September), but is also effective during the dormant
season. Glyphosate is a nonselective herbicide, so care should be taken to
avoid contacting nontarget species. By law, herbicides only may be applied
according to label directions and by licensed herbicide applicators or operators
when working on public properties.
RECOMMENDED PRACTICES ON BUFFER AND SEVERELY DISTURBED SITES
Same as above for high-quality natural communities. In addition, the following
treatments are effective.
Thin-line basal bark treatments with triclopyr herbicides (tradename Garlon) have
demonstrated 95% kill. Undiluted Garlon 4 (or Garlon 4 diluted 50:50 with diesel
fuel) should be applied in a thin, pencil-point line around the base of the plant
6-12 inches (15-30 cm) above the ground. Application can be made with a hand-
held plant sprayer and should be performed during the dormant season to minimize
risk to nontarget species. A narrow band of Garlon 4 encircling the stem is
needed to be effective.
Great care should be exercised to avoid getting any of the mixtures on the ground
near the target plant since some nontarget species may be harmed. This method
should not be used in high quality natural areas because the diesel fuel may kill
vegetation around the tree. Avoid using Triclopyr if rain is forecast for the
following 1-4 days; otherwise runoff can harm nontarget species. By law,
herbicides only may be applied according to label directions and by licensed
herbicide applicators or operators when working on public properties.
Foliar application of dicamba herbicides (available under the tradename Banvel)
and 2,4-d herbicides (available under a variety of brand names,including
Crossbow) can provide total kill with little or no regrowth the following year.
Banvel is mixed at the rate of 1 oz. per gallon of water plus 1/2 oz. of
surfactant. The 2,4-D herbicide should be mixed according to label instructions.
One hundred percent coverage of foliage should be achieved during the growing
season (April-September). Therefore, this control measure is best suited to
shorter plants. Although application can be done any time during the growing
season, summer application (July-August) is especially effective. Banvel and
2,4-D are selective against broadleaf plants, so care must be taken to avoid
contacting desirable, broadleaf vegetation. Do not spray so heavily that
herbicide drips off the target species. Foliar spray of herbicides should only
be used in less sensitive areas because of problems with contacting nontarget
species. The herbicide should be applied while backing away from treated areas
to avoid walking through the wet herbicide.
Although glyphosate (Roundup) is an effective foliar spray when applied during
the growing season, it is not recommended because it is nonselective. Use of
this herbicide as a foliar spray can result in unnecessary damage to target
species.
FAILED OR INEFFECTIVE PRACTICES
Repeated pruning of established plants to ground level without subsequent
herbicide application is not effective for autumn olive control. Each regrowth
results in a thicker stem base and denser branches.
Prescribed burning has not proven effective in controlling established autumn
olive.
ACKNOWLEDGEMENTS
Dr. Robert M. Mohlenbrock and the Southern Illinois University Press generously permitted use of illustrations from their Illustrated Flora of Illinois.
REFERENCES
Ebinger, J. E. and L. Lehnen. 1981. Naturalized autumn olive in Illinois. Illinois State Academy of Science Transactions 74:83-85.
Eckardt, N. 1987. Autumn olive. Element Stewardship Abstract. The Nature Conservancy, Minneapolis, MN. 5 pp.
Kuhns, L. J. 1986. Controlling autumn olive with herbicides. Proc. NE Weed Science Soc. 40:289-294.
Sternberg, G. 1982. Autumn olive in Illinois. Unpublished report, Illinois Department of Conservation, Springfield. 12 pp.
PERSONAL COMMUNICATION
Sternberg, Guy. 1989. Division of Special Services, Illinois Department of Conservation, Springfield, Illinois.
West, Andy. 1989. Division of Natural Heritage, Illinois Department of Conservation, Springfield, Illinois.
Written for the Illinois Nature Preserves Commission by:
Bob Szafoni
Illinois Department of Conservation
R.R. 2, Box 108
Charleston, Illinois 61920