Species Character
DESCRIPTION
Wintercreeper is an evergreen vine forming a dense ground
cover or climbing or trailing to 20 feet (6.1 m) or more high.
It has aerial rootlets and leathery opposite elliptic leaves
that are
veiny beneath. Numerous cultivars exist that exhibit a range
of leaf sizes and colors. Branches are densely covered with minute
warts. The small greenish flowers occur in clusters, with a long
flower stalk. Fruits are globose and smooth in an orange capsule,
maturing in June and July.
SIMILAR SPECIES
This vine differs from bittersweet (Celastrus spp.) because bittersweet has alternate leaves. It can be distinguished from other Euonymus spp. in that it is a vine rather than an erect shrub or tree. Wintercreeper 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
Wintercreeper occurs infrequently in the eastern U.S. It was introduced from Asia as a groundcover. In Missouri, it is frequently found near urban centers, with heavy infestations in woodlands in the St. Louis and Kansas City vicinities. It is commonly sold by nurseries today as an ornamental groundcover and may spread from plantings in any part of the state.
HABITAT
This species occurs as a cultivated plant at home sites. It has spread into several types of forest, including floodplain, mesic and dry-mesic forest. It invades natural openings and relatively undisturbed forests.
LIFE HISTORY
Wintercreeper is a very aggressive perennial woody vine that climbs on rocks and trees as well as spreading over the ground. It tolerates full sun, heavy shade, and most soil moisture conditions, except extremely wet conditions. It appears to be spread by birds that eat its seeds.
EFFECTS UPON NATURAL AREAS
Wintercreeper can cover the ground and vegetation and eliminate native groundcover species in mesic and dry-mesic forests. It is a serious potential threat because it spreads so rapidly and replaces spring ephemerals. The Shirling Sanctuary in Kansas City's Swope Park provides an example of a mesic forest that has been seriously degraded by the aggressive spread of wintercreeper.
Control Recommendations
Recommended Practices in Natural Communities of High Quality
Initial effort in areas of heavy infestation
Vines should be cut by hand and each cut stem sprayed with Roundup (a formulation of glyphosate) just after the last killing frost. While the Roundup label recommends a 50-100% concentration of Roundup for stump treatment, a 20% concentration has proven effective. A squirt bottle may be used for spot treatment or individual stumps can be painted by hand using a sponge applicator. Treatment should be in late winter when most native vegetation is dormant and prior to the emergence of spring wildflowers. Care should be taken to avoid contacting non-target species with the herbicide. By law, herbicides may only be applied as per label instructions
Effort in areas of light infestation
In small areas, where practical, individual vines should be pulled up by the roots and removed from the area.
Maintenance control
The most effective control is to totally eradicate the species from the surrounding area where possible. Invading individuals should be pulled and removed as soon as possible after recognition.
Recommended Practices on Lands Other Than High-Quality Natural Areas
Initial effort in areas of heavy infestation
Same as above in areas where hand labor is available and where area affected is relatively small. In large areas, foliar spraying with Crossbow (mixture of 2,4-D and triclopyr) in autumn after the first frost can reduce the population. Crossbow should be mixed according to label instructions for foliar application and applied as a foliar spray. Spraying should be completed prior to emergence of spring wildflowers. Care should be used to avoid contacting non-target plants with herbicide. The herbicide should be applied while backing away from the treated area to avoid walking through the wet herbicide.
Effort in areas of light infestation
Same as described for high-quality natural areas.
Maintenance control
Same as described for high-quality natural areas.
Failed or Ineffective Practices
The following practices should be avoided:
- hand control: slow and labor intensive, making it impractical for large infestations.
- mowing: ineffective without chemical treatment and not practical in woodland.
- fire: often not desirable in mesic woodland.
- herbicides: should not be used during growing season when spring wildflowers and other native species are likely to be affected.
- manipulating water levels: not practical on sites where it occurs.
- biological control: no effective biological controls are known that are feasible in natural areas.
- introduction of competitive species: no native species known that can compete.References
References
Dirr, M. A. 1977. Manual of woody landscape plants: their identification, ornamental characteristics, culture, propagation, and uses. Stipes Publishing Co., Champaign, Illinois. 536 pp. Fernald, M. L. 1950. Gray's manual of botany, eighth edition. American Book Co., New York. 1632 pp. Mohlenbrock, R. H. 1986. Guide to the vascular flora of Illinois. Southern Illinois University Press, Carbondale. 507 pp. Petrides, G. A. 1972. A field guide to trees and shrubs. Peterson Field Guide Series. Houghton Mifflin Co., Boston Massachusetts. 428 pp. Schwegman, J. E. 1988. Exotic invaders. Outdoor Highlights, mid-March issue, pp. 6-11. Wharton, M. E., and R. W. Barbour. 1973. Trees and shrubs of Kentucky. Kentucky Nature Studies 4. The University Press of Kentucky, Lexington. 582 pp.
Personal Communications
Kurz, Don. 1988. Natural History Section, Missouri Department of Conservation, Jefferson City, Missouri. McFall, Don. 1988. Division of Natural Heritage, Illinois Department of Conservation, Springfield, Illinois. Olson, Steve. 1988. Division of Nature Preserves, Indiana Department of Natural Resources, Tell City, Indiana. Schwegman, John. 1988. Division of Natural Heritage, Illinois Department of Conservation, Springfield, Illinois. Stritch, Larry. 1988. Shawnee National Forest, United States Forest Service, Harrisburg, Illinois.
Adapted from material written for the Illinois Nature Preserves Commission by: Max Hutchison The Nature Conservancy Route 1, Box 53E Ullin, Illinois 62992
