autumn olive (Elaeagnus umbellata)
SCIENTIFIC SYNONYMS: There are no scientific synonyms
for Elaeagnus umbellata.
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name for autumn-
olive is Elaeagnus umbellata Thunb. One variety has been recognized -
Elaeagnus umbellata Thunb. var. parvifolia (Royle) Schneid. The Atlas
of Virginia Flora lists var. parvifolia as the only variety of Elaeagnus
umbellata occurring in Facquier County. Several cultivars have been
developed by the U.S. Department of Agriculture, Soil Conservation
Service, and distributed for wildlife and other conservation uses.
NATIVE STATUS: Introduced, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Autumn-olive is a
many-branched, deciduous shrub or shrubby tree, growing 10 to16 feet
(3-5 m) tall. Leaves are alternate simple, and variable in size, ranging
from 0.4 to 3 inches (1-8 cm) long and 0.4 to 1.6 inches (1-4 cm) wide.
Thorns several inches in length are formed on spur branches. Autumn-
olive fruits are single-seeded drupes, 0.2 to 0.4 inches (4-10 mm) in
diameter, produced on pedicels. Autumn olive forms root nodules induced
by symbiosis with actinomycetes in the soil. This symbiosis permits the
fixation and subsequent utilization of atmospheric nitrogen.
REGENERATION PROCESS: There is very little published information
describing regeneration biology in autumn-olive. Research is needed to
determine the precise nature of asexual regeneration, conditions that
promote or constrain seedling establishment and early growth, and the
role of soil-stored seed in autumn-olive invasiveness.
Autumn-olive is open-pollinated, often by insects. Mature plants can
produce about 30 pounds (14 kg) of fruit annually. Thirty pounds of
fruit is generally equivalent to about 3 pounds (1.4 kg) of seed, or about
66,000 seeds. Under favorable conditions, autumn-olive can produce
fruit by 3 to 5 years of age. Fruit production is reduced by shading. Seeds
are dispersed by frugivorous birds and, to a lesser extent, small mammals.
When burned, mowed, or cut, autumn olive plants vigorously resprout.
SITE CHARACTERISTICS: Autumn-olive has been planted throughout
much of eastern North America for various purposes, and has subsequently
escaped into a variety of natural and seminatural habitats. For example,
Invasive Plant Atlas of New England lists the following general habitats
where autumn-olive may be found in New England: abandoned field, aban-
doned gravel pit, early-successional forest, edge, pasture, planted forest,
railroad right-of-way, roadside, utility right-of-way, vacant lot, yard, or
garden. It is probably most prolific on disturbed or ruderal sites.
Autumn-olive grows best on deep, relatively coarse-textured soils that
are moderately-well to well drained. It does less well on very dry soil
and usually fails on very shallow, poorly drained, or excessively wet soil.
Autumn-olive does not require highly fertile soil, and it appears to thrive
equally well on soils ranging from "moderately acid to moderately alkaline".
In a study conducted in Ontario, escaped autumn-olive is found in a variety
of dry to mesic sandy, forested and open to sparsely shaded habitats, with
soil pH from 5-7. It is most invasive in areas of dry sandy soils. Although it
has been cultivated on fine-textured, periodically wet soils, it is generally
not invasive on such sites.
SUCCESSIONAL STATUS: Autumn-olive appears best adapted to
early-successional habitats in North America. It has been called "moder-
ately" shade tolerant, but is thought to be generally absent from areas
with very low light intensity, such as under a dense forest canopy.
Autumn-olive plants are generally restricted to "open canopy areas"
within the interior of "old-growth" forests, suggesting autumn-olive is
"not well adapted to low-light conditions." However, low-light situations
do not completely eliminate the possibility of autumn olive becoming
establishing under a forest canopy.
SEASONAL DEVELOPMENT: In the central and southern Appalachian
regions, autumn-olive fruit ripens in August and September. Fruit generally
remains on the plant until late winter. Autumn-olive generally produces
leaves in early spring, prior to most native plants.
GENERAL DISTRIBUTION: Autumn-olive occurs throughout the
eastern United States, from Maine, west to Wisconsin, Iowa, Nebraska,
Kansas, Arkansas, and Louisiana, and south into Florida. It also occurs
in southern and eastern Ontario and Hawaii. Elaeagnus umbellata var.
parvifolia has the same distribution as autumn-olive.
Northern distribution of invasive autumn-olive populations in North
America may be limited by cold intolerance from USDA climate zone 5
north, although one cultivar has been described as "hardy" to zone 6.
Autumn-olive is native to Asia and was introduced to North America
SKY MEADOWS DISTRIBUTION:
Shrub specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
The specific distribution for autumn-olive has not been determined.
HABITAT TYPES AND PLANT COMMUNITIES: Autumn-olive is
found across many habitats in North America, and may be associated
with a variety of plant taxa, functional guilds and communities. As of this
writing, there is very little published information concerning habitat types
and plant communities where autumn-olive might invade. Autumn-olive
is not a climax dominant or indicator species in habitat type classifications.
In general, invasive autumn-olive impacts native biotic communities
in eastern North America by displacing native plants. Invasive popula-
tions can supplant native habitat, sometimes forming dense thickets.
Prodigious seed production and widespread seed dispersal by frugivorous
birds probably contribute to its invasiveness.
IMPORTANCE AND USES: Autumn-olive has been promoted as a
beneficial wildlife species and planted in wildlife management areas in
the eastern U.S. to provide food and cover. Fruit remains on the plant
until late winter, potentially becoming an important wildlife food during
periods of seasonal food scarcity. Fruits are consumed by a variety of
wildlife, including songbirds, northern bobwhite, ruffed grouse, mourning
doves, ring-necked pheasants, wild turkeys, mallards, raccoons, skunks,
opossums, and black bears. Songbirds that eat autumn-olive fruit include:
gray catbirds, hermit thrushes, wood thrushes, house finches, American
robins, cardinals, cedar waxwings, common grackles, evening grosbeaks,
fox sparrows, house sparrows, song sparrows, white-throated sparrows,
mockingbirds, myrtle warblers, purple finches, rufous-sided towhees,
starlings, tree swallows, and veerys. Autumn-olive is also browsed by
Autumn-olive provides cover for wildlife, especially songbirds, game
birds, and rabbits.
Autumn-olive has been promoted for reclamation of mine spoils and
other disturbed soils. It has been planted for reclamation of surface coal
mine sites because it is tolerant of low pH soil conditions often found on
these sites. It has also been suggested for use in stabilizing eroded soils
in exposed coastal areas due to its salt spray tolerance. An additional
benefit to planting autumn-olive in these and other situations, where
reclamation of disturbed and frequently nutrient-poor soils is an impor-
tant objective, is its ability to fix atmospheric nitrogen.
Autumn olive has been a recommended species for planting as a tall
shrub component in windbreaks in the Great Plains, in part due to its
wildlife food and cover value.
Autumn-olive is used in plantations for companion planting with black
walnut to enhance black walnut productivity. It is thought autumn olive
enhances black walnut growth by increasing ecosystem nitrogen pools
through nitrogen fixation and by decreasing herbaceous competition.
As described by one researcher, autumn olive can form "a nearly impen-
etrable thicket" and were "commonly the only understory species present."
Crooked Run Valley