English Ivy
Hedera helix L.

SOURCE: The following information on this species is taken, in part, from the Plant Conservation Alliance, Alien Plant Working Group, Weeds Gone Wild website, Fact Sheets. The Fact Sheet information for this species can be found at http://www.nps.gov/plants/alien/factmain.htm. Some pictures have been added from www.invasive.org. Specific species management and control information is provided elsewhere. Check the website links provided to check for future updates. The last update for this PCA fact sheet is December 2000.

NATIVE RANGE: Europe, western Asia, and northern Africa

DESCRIPTION: English ivy is an evergreen climbing vine in the ginseng family (Araliaceae). Vines attach to the bark of trees, brickwork, and other surfaces by way of numerous, small root-like structures, which exude a glue-like substance. Older vines are known to reach a foot in diameter.

Photo: Jil M. Swearingen, U.S. National Park Service, Washington, DC

Leaves are dark green, waxy, somewhat leathery, and are arranged alternately along the stem. English ivy has many recognized leaf forms, the most common being a 3-lobed leaf with a heart-shaped base. Leaves in full sun are often unlobed, oval and have wedge-shaped bases.

Photo: James H. Miller, USDA Forest Service, www.invasive.org.

Umbrella-like clusters of small, greenish-white flowers appear in the fall if sufficient sunlight is available. Fruits mature in Spring and are black with a fleshy outer covering enclosing one to a few hard, stone-like seeds.

NOTE: Compounds in English ivy are somewhat toxic and include glycosides that cause vomiting, diarrhea, nervous conditions and dermatitis in sensitive individuals. This characteristic helps ensure spread of the seeds by many native songbirds that are attracted to the black berries in Spring when other food sources are limited.

ECOLOGICAL THREAT: English ivy is an aggressive invader that threatens all vegetation levels of forested and open areas, growing along the ground as well as into the forest canopy. The dense growth and abundant leaves, which spring from the stems like small umbrellas, form a thick canopy just above the ground, and prevent sunlight from reaching other plants.

Photo: Randy Cyr, GREENTREE Technologies, www.invasive.org

Similarly, vines climbing up tree trunks spread out and surround branches and twigs, preventing most of the sunlight from reaching the leaves of the host tree. Loss of host tree vigor, evident within a few years, is followed by death a few years later. The added weight of vines makes infested trees susceptible to blow-over during storms. English ivy also serves as a reservoir for bacterial leaf scorch (Xylella fastidiosa), a plant pathogen that is harmful to native trees such as elms, oaks, and maples. English ivy is a popular plant, recommended by Cooperative Extension offices for use as a low maintenance alternative to lawns. It is widely used by homeowners, horticulturists, landscape contractors, parks departments and others desiring a fast-growing, low maintenance, evergreen groundcover. Once established at a site, English ivy can be expected to move beyond its intended borders into neighboring yards, parks and other lands, either by vegetative means or by seed.

DISTRIBUTION IN THE UNITED STATES: English ivy occurs in at least 26 states and the District of Columbia, where it is one of the most abundant and widespread invasive plants. Click here to see a distribution map.

HABITAT IN THE UNITED STATES: English ivy infests woodlands, forest edges, fields, hedgerows, coastal areas, salt marsh edges, and other upland areas, especially where some soil moisture is present. It does not grow well in extremely wet conditions and is often associated with some form of land disturbance, either human-caused or natural.

BACKGROUND: English ivy was probably first introduced to the US by European immigrants and is widely sold as an ornamental plant for landscapes throughout the US.

BIOLOGY & SPREAD: English ivy reproduces vegetatively and by seed, which is dispersed to new areas primarily by birds, including English house sparrows, European starlings, robins, Stellar jays, and cedar waxwings. New plants grow easily from cuttings or from stems making contact with the soil.

For more information on English ivy, please contact:
Sandra Diedrich, sddivy@teleport.com and http://www.noivyleague.com
Kris Johnson, Great Smoky Mountains National Park, Gatlinburg, TN
Sue Salmons, Rock Creek Park, Washington, D.C., sue_salmons@nps.gov
Jil Swearingen, National Park Service, Washington, D.C., jil_swearingen@nps.gov
National Invasive Species Information Center, http://www.invasivespeciesinfo.gov
Southeast Exotic Pest Plant Council - Invasive Plant Manual, http://www.se-eppc.org/manual/
The Nature Conservancy Invasive Species Initiative, http://tncweeds.ucdavis.edu/esadocs.html
USDA Forest Service - Nonnative Invasive Plant of Southern Forests - http://www.invasive.org/eastern/srs/EI.html.

SUGGESTED ALTERNATIVE PLANTS: Attractive native vines are available that provide nectar for hummingbirds, butterflies, and other insects, serve as host plants for native insects, and provide food for many wildlife species. Vines native to the eastern U.S. include Allegheny pachysandra (Pachysandra procumbens), American or common bittersweet (Celastrus scandens), trumpet creeper (Campsis radicans), Virginia creeper (Parthenocissus quinquefolia), passionflower vine (Passiflora lutea), Dutchman's pipe (Aristolochia macrophylla), and native wisteria* (Wisteria frutescens).

* If you wish to plant wisteria, make certain that it is the native species. Two commonly planted ornamental wisterias, Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda), are exotic and aggressive invaders. Please consult the native plant society in your state for more information on species native to your particular area.

AUTHORS: Jil M. Swearingen, U.S. National Park Service, Washington, DC. Sandra Diedrich.

REFERENCES:

Collins, Christi. 1994. Some notes on Hedera helix The English ivy. The Nature Conservancy.
Dirr, Michael A. 1990. Manual of wody landscape plants: their identification, ornamental characteristics, culture, propagation and uses. Stipes Publ. Company, Champaign, IL.
Fernald, M.L. 1970. Gray's Manual of Botany. Eighth ed. D. Van Nostrand Co., New York, N.Y. p.1078.
Harty, Francis M. 1993. How Illinois kicked the exotic species habit. Pp. 195-209. In B.N. McKnight (ed.), Biological Pollution, Indiana Acad. Sci., Indianapolis, IN. 261 pp.
Lewis, W.H., and M. Elvin-Lewis. 1977. Meidical Botany: Plants Affecting Man's Health. John Wiley and Sons, Inc.
McElrone, A., Sherald, J. L. and Pooler, M. R. Identification of alternative hosts of Xylella fastidiosa in the Washington, DC area using nested polymerase chain reaction (PCR). J. Arboric. (In press)
Radford, A.E., H.E. Ahles, and C. Ritchie Bell. 1968. Manual of the Flora of the Carolinas. The University of North Carolina Press, Chapel Hill, NC. Pp. 758-9.
Randall, J. M., and Marinelli, J. 1996. Invasive Plants: Weeds of the Global Garden. Brooklyn Botanic Garden, Handbook #149. p. 7-11.
Salmons, S. 2000. Rock Creek Park Invasive Non-native Plant Mitigation Program, Final Report. January, 23 pp.
Sherald, J. L. and Kostka, S. J. 1992. Bacterial leaf scorch of landscape trees caused by Xylella fastidiosa. J. Arboric. 18: 57-63.
The Nature Conservancy. . English ivy: Element Stewardship Abstract. In: Wildland Invasive Species Program, Weeds on the Web. http://www.tnc.org
Thomas, L.K., Jr. 1980. The impact of Three Exotic Plant Species on a Potomac Island. National Park Service Scientific Monograph Series, no. 13. 179 pp.
Uphof, J.C.T. 1968. Dictionary of Economic Plants. J. Cramer Publishing Co., Lehre, Germany.
Virginia Native Plant Society. 1995. Invasive Alien Plant Species of Virginia: English ivy (Hedera helix).

Plant Conservation Alliance, Alien Plant Working Group.

Management and Control Information

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