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United States Department of Agriculture

Forest Service

Northern Research Station

An Assessment of Autumn Olive in Northern U.S. Forests Research Note NRS-204

This publication is part of a series of research notes that provide an overview of the invasive plant species monitored on an 

extensive systematic network of plots measured by the Forest Inventory and Analysis (FIA) program of the U.S. Forest Service, 

Northern Research Station (NRS). Each research note features one of the invasive plants monitored on forested plots by NRS FIA in 

the 24 states of the midwestern and northeastern United States.

Background and Characteristics

Autumn olive (Elaeagnus umbellata), a shrub of the Oleaster 

family (Elaeagnaceae), is native to eastern Asia and arrived in the 

United States in the 1830s. This vigorous invader was promoted 

for wildlife, landscaping, and erosion control. Tolerant of poor 

quality sites and full sun, it was often used for mine reclamation. 

Autumn olive disrupts native plant communities that require 

infertile soil by changing soil fertility through fixing nitrogen. 

Where it establishes, it can form dense thickets that shade out 

native plants (Czarapata 2005, Kaufman and Kaufman 2007, 

Kurtz 2013). Aside from the negative impact, autumn olive has 

important culinary and medicinal properties (Fordham et al. 

2001, Guo et al. 2009).

Description

Growth: woody, perennial shrub to 20 feet, often multistemmed; simple, alternate leaves with slightly wavy margins, 

green upper leaf surfaces, and silvery bottoms; shrubs leaf out 

early in the spring and retain leaves late in the fall.

Flowers: fragrant, tubular, creamy to light yellow, with 4 petals 

(Fig. 1); appear singly or in clusters in leaf axils; spring.

Fruit: abundant small (<0.5 inch) green fruits mature to pink/red 

with silver to coppery spots (Fig. 2); each has one seed; seeds are 

dispersed by birds and mammals and germinate readily.

Reproduction: seeds; suckers.

Twigs and branches: twigs are silvery to golden brown with a 

speckled appearance; older branches are gray, often with thorns 

(Fig. 3).

Habitat: wide variety of habitats with low stocking such as 

prairies, old fields, open forests, and wastelands; rare in dense 

forests or on wet sites. 

Control: various mechanical and chemical methods; resprouts 

readily (Czarapata 2005, Kaufman and Kaufman 2007).

Growth Conditions and Range

Autumn olive has high drought tolerance, is hardy to -23 °F, 

requires a minimum of 150 frost free days, a pH between 5.0 

and 7.5, 28 to 45 inches of precipitation, and a minimum rooting 

depth of 18 inches. It is currently found in 36 states as well as 

one Canadian province (Ontario) (NRCS 2016).

Figure 1.—Autumn olive flowers. Photo by Chris Evans, 

University of Illinois, from Bugwood.org, 1380001.

Figure 2.—Autumn olive fruit. Photo by Leslie J. Mehrhoff, 

University of Connecticut, from Bugwood.org, 5455269.

Figure 3.—Autumn olive thorns. Photo by James H. Miller, 

U.S. Forest Service, from Bugwood.org, 0016044.
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Autumn Olive Presence on Phase 2 Invasive Plots, 2014

FIA crews visited 6,360 forested Phase 2 (P2) invasive plots 

across the NRS region in the 2014 inventory (2009-2014). 

On P2 invasive plots, 40 invasive plant species1

 (IPS) (39 

species and one undifferentiated genus [nonnative bush 

honeysuckles]2) are monitored. On each of these plots, 

various characteristics are recorded including the occurrence 

and coverage of IPS, as well as the standard forest variables 

measured on P2 plots (e.g., tree diameter, height). Overall, 

50.3 percent of forested plots have one or more of the 

monitored invasives present.

Autumn olive is widespread throughout the region, occurring 

on 429 plots (6.7 percent). It is found in 19 of the 24 NRS 

states (Fig. 4). Field crew did not observe this invasive shrub 

in Massachusetts, Minnesota, Nebraska, North Dakota, 

and Rhode Island. These results differ slightly from the 

Plants Database (NRCS 2016), which reports autumn olive’s 

presence in Nebraska and Rhode Island, but it is important 

to remember this inventory samples only forest land. West 

Virginia has 23.2 percent of plots with autumn olive, the 

greatest percent of all northern states. This invasive shrub 

is also prevalent in Ohio (19.9 percent of plots), Indiana 

(17.7 percent of plots), and Illinois (16.0 percent). For the 

2014 inventory, autumn olive is the sixth most commonly 

observed invasive species, after multiflora rose (28.8 percent 

of P2 invasive plots), nonnative bush honeysuckles (18.4 

percent), garlic mustard (9.8 percent), Japanese honeysuckle 

(7.5 percent), and reed canarygrass (7.4 percent). Additional 

information about the invasives monitored and county level 

occurrence maps for the NRS region from 2005 through 2010 

can be found in Kurtz (2013).

Figure 4.—Percentage of Phase 2 invasive plots with autumn olive, 2014. 

Percentages are rounded to the nearest whole number.

Autumn olive infestation. Photo by Leslie J. Mehrhoff, University 

of Connecticut, from Bugwood.org.

1 Autumn olive (Elaeagnus umbellata), black locust (Robinia pseudoacacia), Bohemian knotweed (Polygonum xbohemicum), bull 

thistle (Cirsium vulgare), Canada thistle (Cirsium arvense), Chinaberry (Melia azedarach), common barberry (Berberis vulgaris), 

common buckthorn (Rhamnus cathartica), common reed (Phragmites australis), creeping jenny (Lysimachia nummularia), dames 

rocket (Hesperis matronalis), English ivy (Hedera helix), European cranberrybush (Viburnum opulus), European privet (Ligustrum 

vulgare), European swallow-wort (Cynanchum rossicum), garlic mustard (Alliaria petiolata), giant knotweed (Polygonum 

sachalinense), glossy buckthorn (Frangula alnus), Japanese barberry (Berberis thunbergii), Japanese honeysuckle (Lonicera 

japonica), Japanese knotweed (Polygonum cuspidatum), Japanese meadowsweet (Spiraea japonica), leafy spurge (Euphorbia 

esula), Louise’s swallow-wort (Cynanchum louiseae), multiflora rose (Rosa multiflora), Nepalese browntop (Microstegium 

vimineum), nonnative bush honeysuckles (Lonicera spp.), Norway maple (Acer platanoides), Oriental bittersweet (Celastrus 

orbiculatus), princesstree (Paulownia tomentosa), punktree (Melaleuca quinquenervia), purple loosestrife (Lythrum salicaria), reed 

canarygrass (Phalaris arundinacea), Russian olive (Elaeagnus angustifolia), saltcedar (Tamarix ramosissima), Siberian elm (Ulmus 

pumila), silktree (Albizia julibrissin), spotted knapweed (Centaurea stoebe ssp. micranthos), Chinese tallow (Triadica sebifera), tree 

of heaven (Ailanthus altissima).

2 The 39 IPS and one undifferentiated genus (nonnative bush honeysuckles) are hereafter referred to as “invasive species”, 

“invasive plants”, “invasives”, or “IPS”.
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Autumn Olive Cover on Phase 2 Invasive Plots

The percentage cover of autumn olive is shown in 

two figures, one that illustrates cover by state (Fig. 5) 

and a second that focuses on plot level data (Fig. 6). It 

is important to use caution when looking at Figure 5 

because in some states the overall averages are driven by 

a small number of plots (e.g., Kansas and South Dakota). 

For the states with a low number of observances, Figure 

6 is more informative since individual plot values can be 

assessed. Due to the large number of plots monitored, 

plots without autumn olive are not shown. Autumn olive 

is most prevalent in the southern part of the region, 

with the highest average percentage cover on plots 

in Pennsylvania (6.5 percent). These maps, along with 

Figure 4, reveal important information related to the 

presence and abundance of autumn olive in the NRS 

region. Over time these maps will allow us to assess 

changes in abundance and spread.

Figure 6.—Average percent cover3 of autumn olive observances on Phase 2 invasive plots, 2014. Percentages are rounded 

to the nearest whole number.

3 Average percent cover is calculated for plots with autumn olive based on subplot data for the portion of the plot that is forested. Each 

FIA plot consists of four circular 1/24-acre subplots located at the corners and center of an equilateral triangle that is 208 feet on a side.

Figure 5.—Average percent cover3 of autumn olive on Phase 2 

invasive plots, 2014. Percentages are rounded to the nearest whole number.
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Characteristics of Plots with Autumn Olive

The P2 invasive data suggest that autumn olive is more 

common on plots near roads. There is a significant difference 

(t-test; p<0.05) in the distance to the nearest road for plots 

with and without autumn olive (Fig. 7). However it is important 

to note the variability in both road density and autumn 

olive occurrence across the region before making further 

conclusions. Several studies have highlighted the effect of roads 

on invasive distribution. Roads are a conduit for seed dispersal, 

alter light and nutrient availability, and drainage. Vehicles 

traveling on roads carry propagules of many exotics which 

become dispersed along them. Roads are an important vector 

for IPS (Kurtz and Hansen 2013, Lundgren et al. 2004, Predick 

and Turner 2008). Due to the effects of roads and other types of 

fragmentation, it is important to strive to keep forest land intact.

Figure 7.—Average distance to the nearest road 

for plots with and without autumn olive, 2014. 

Error bars show a 68 percent confidence interval for the 

observed mean.

0

500

1,000

1,500

2,000

2,500

Road distance (ft)

Absent Present

Tree cover also differs for plots with and without autumn olive. The 2014 data suggest that there are fewer trees per acre on plots 

with autumn olive (Fig. 8 and 9) (t-test; p<0.05). Since the study has only been underway for a short time (complete implementation 

across all of the NRS region in 2007), it is difficult to assess whether the invasives are influencing tree regeneration and growth, 

or if the IPS are establishing where there is reduced tree cover and less competition. Continued investigation into this matter is 

important because these plants can outcompete native species and without adequate understory regeneration to replace the aging 

overstory, the future of the forest remains in question. These preliminary investigations are important as they suggest there is a 

difference between plots with and without autumn olive.

0

100

200

300

400

500

600

700

800

Trees per acre ≥1 inch d.b.h

Absent Present 0

20

40

60

80

100

120

140

160

180

Trees per acre ≥5 inches d.b.h.

Absent Present

Further analysis of plots with and without autumn olive 

shows that plots without autumn olive tend to be more 

forested than plots with autumn olive (Fig. 10) (t-test; p<0.05). 

Overall, plots with this invader are 3.0 percent less forested 

when compared to plots without autumn olive.

Monitoring IPS offers insight on the status, trends, 

distribution, and population size, as well as helps to detect 

new populations. The trends found in this research note are 

important and need to be monitored in the future to help 

elucidate important factors related to the presence of these 

invasives as well as to find out the impacts these species are 

causing on biota and ecosystems. This research is valuable to 

land managers and other concerned individuals as it provides 

nonbiased data to help make well-informed management 

decisions.

Figure 10.—Percentage of the plot that is forested for plots 

with and without autumn olive, 2014. Error bars show a 68 percent 

confidence interval for the observed mean.

0

10

20

30

40

50

60

70

80

90

Percent forested

Absent Present

Figure 8.—Trees per acre ≥1 inch d.b.h. with and without 

autumn olive, 2014. Error bars show a 68 percent confidence interval 

for the observed mean.

Figure 9.—Trees per acre ≥5 inches d.b.h. with 

and without autumn olive, 2014. Error bars show 

a 68 percent confidence interval for the observed mean.
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Citation for this Publication

Kurtz, Cassandra M.; Hansen, Mark H. 2016. An assessment of autumn olive in northern U.S. forests. Res. Note NRS-204. 

Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 5 p.

FIA Program Information

Bechtold, W.A.; Patterson, P.L., eds. 2005. The enhanced Forest Inventory and Analysis Program: national sampling 

design and estimation procedures. Gen. Tech. Rep. SRS-80. Asheville, NC: U.S. Department of Agriculture, Forest Service, 

Southern Research Station. 85 p.

Smith, W.B. 2002. Forest inventory and analysis: a national inventory and monitoring program. Environmental Pollution. 

116: 233-242.

U.S. Forest Service. 2014. Forest inventory and analysis national core field guide, Vol. 1: field data collection procedures 

for phase 2 plots, ver. 6.1. Available at www.fia.fs.fed.us/library/field-guides-methods-proc/ (accessed February 22, 2016). 

References

Czarapata, E.J. 2005. Invasive plants of the upper Midwest: an illustrated guide to their identification and control.

Madison, WI: University of Wisconsin Press. 215 p. 

Fordham, I.M.; Clevidence, B.A.; Wiley, E.R.; Zimmerman, R.H. 2001. Fruit of autumn olive: a rich source of lycopene.

HortScience. 36(6): 1136-1137.

Guo, X.; Yang, L.; Hu, H.; Yang, L. 2009. Cloning and expression analysis of carotenogenic genes during ripening of 

autumn olive fruit (Elaeagnus umbellata). Journal of Agricultural and Food Chemistry. 57: 5334-5339.

Kaufman, S.R.; Kaufman, W. 2007. Invasive plants: a guide to identification and the impacts and control of common 

North American species. Mechanicsburg, PA: Stackpole Books. 458 p.

Kurtz, C.M. 2013. An assessment of invasive plant species monitored by the Northern Research Station Forest Inventory 

and Analysis Program, 2005 through 2010. Gen. Tech. Rep. NRS-109. Newtown Square, PA: U.S. Department of Agriculture, 

Forest Service, Northern Research Station. 70 p.

Kurtz, C.M.; Hansen, M.H. 2013. An assessment of multiflora rose in northern U.S. forests. Res. Note NRS-182. Newtown 

Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 5 p.

Lundgren, M.R.; Small, C.J.; Dreyer, G.D. 2004. Influence of land use and site characteristics on invasive plant abundance 

in the Quinebaug Highlands of southern New England. Northeastern Naturalist. 11(3): 313-332.

Natural Resource Conservation Service (NRCS). 2016. The PLANTS database. Greensboro, NC: U.S. Department of Agriculture, 

Natural Resource Conservation Service, National Plant Data Team. http://plants.usda.gov (accessed Feb. 22, 2016).

Predick, K.I.; Turner, M.G. 2008. Landscape configuration and flood frequency influence invasive shrubs in floodplain 

forests of the Wisconsin River (USA). Journal of Ecology. 96: 91-102.

Additional Invasive Plant Information

Alien Plant Invaders of Natural Areas (PCA, National Park Service): http://www.nps.gov/plants/alien/factmain.htm

Invasive and Exotic Plants: http://www.invasive.org/species/weeds.cfm

Invasive Plant Atlas of New England: http://www.eddmaps.org/ipane/

Invasive Plant Atlas of the United States: http://www.invasiveplantatlas.org/index.html

Midwest Invasive Plant Network: http://mipn.org/

Contact

Analyst: Cassandra Kurtz, (651) 649-5149; cmkurtz@fs.fed.us

Page 1 and 5 photo header by: Leslie J. Mehrhoff, University of Connecticut, from Bugwood.org

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