User ID
Password
Home  About  Contact
Scientific Name:

Common Name:

Lonicera japonica Thunb.
Japanese honeysuckle
Family: Caprifoliaceae

USDA Plant Code: LOJA

Habitat: Terrestrial; forest, waste areas

Growth Habit: Perennial Vine

Native Environment: East Asia

Introduction



Japanese Honeysuckle Vine Climbing Up a Tree
Problems Caused
Japanese honeysuckle was introduced from Japan in the early 1800s and now is one of the most commonly encountered exotic weeds in the MidSouth. This species frequently can be observed overtopping and often displacing native plants and forestry species in any habitat, but particularly where edges have been created – by natural or human activities. Japanese honeysuckle also is somewhat shade tolerant and can be found even in relatively densely canopied forest. This species perenniates with the aid of well developed root and rhizome systems, by which it also is capable of spreading vegetatively, in addition to rooting at nodes along aboveground stems. Both features contribute substantially to its rapid dominance over native vegetation once established.

Regulations
Japanese honeysuckle is listed as a noxious weed in CT, MA, NH, and VT. In the southeast, Japanese honeysuckle is considered a severe invasion threat in KY, SC, and TN. It is considered one of the top ten invasive plants in GA, and is listed as a category one invasive in Florida. It is not presently listed in any noxious weed legislation in southern states.

Description


Vegetative Growth
Japanese honeysuckle exhibits a semi-evergreen to evergreen life cycle and is readily identified during winter by its persistent green foliage. Its vines may climb and/or spread along the ground to lengths of 24 m (80 ft). These sprawling vines may form extensive cover over existing vegetation, which ultimately will be choked out by the dense canopies formed by Japanese honeysuckle. This species produces a slender woody vine that can grow up to 5 cm (2 in) in diameter. The mature stems typically are lighter shades of brown and hairy, the bark of which will become fissured and flake as the plant ages.

Leaves and branching stems are arranged oppositely on the main stem. Leaves are ovate to elliptic or longer with rounded bases and tips that may be blunt-pointed to round. The leaves range in length from about 4 to 6.5 cm (1.5 to 2.5 in) and are about half as wide. Leaf margins of mature leaves usually are entire (unlobed) but young leaves and those in dense shade often will be highly lobed. Both surfaces of the leaf, as well as the young stems, will produce some degree of pubescence, and the undersurface of leaves usually appears whitish.


Flowers of Japanese Honeysuckle
Flowering
As mentioned above, Japanese honeysuckle is capable of vegetative growth by root and rhizome systems, in addition to rooting at nodes along aboveground stems. It can be seen flowering from April to August, or later, in our region, and this contributes to considerable success in sexual reproduction. Pairs of white to pale yellow (sometimes pinkish, but not red, as in our native honeysuckle) flowers are produced in leaf axils. These flowers are well known in the southern states for their fragrant odor during the spring and summer; this species is so well known that many are unaware of its exotic invasive status. The flowers also are visually attractive, with their five-lobed corollas and long, thin floral tube. Fruit and seeds typically are produced during summer and can be observed on the plants into the following spring. The fruit are more or less spherical in outline, ripening from green to a glossy black and producing two to three seeds each.

Dispersal
Animals are known to disseminate fruit and seed of this species, thus ensuring its establishment along edges, fence lines, hedgerows, and similar habitats.

Spread By
Japanese honeysuckle has been widely used in horticulture, and has escaped cultivation.

Habitat


Japanese honeysuckle primarily is an edge species, occurring most commonly and in highest densities along woodland edges, in thickets, and along fence rows; however, it also can be found in mature forests, thriving in tree gaps created by natural or artificial disturbance and persisting in partially shaded areas.

Distribution


United States
Japanese honeysuckle was introduced to the United States in the early 1800s as an ornamental plant, but also has been used in attempts at erosion control and for wildlife cover and food. In fact, it is reported that this species still is recommended as a wildlife food in some parts of the US. Japanese honeysuckle occurs in at least 38 states from California across the southern and midwestern states to New England and the Great Lakes region. It also is reported from Hawaii, Puerto Rico, and Québec, Canada.

MidSouth
Japanese honeysuckle is widespread throughout the MidSouth states.

IPAMS Surveys:

Control Methods


Biological
No biological control agents are known for this species.

Chemical Control Options for Japanese Honeysuckle
Herbicide Method Rate
glyphosate Foliar spray, Broadcast 2 to 3 quarts per acre
Foliar spray, Spot treatment 2% solution
triclopyr Foliar spray, Broadcast 3 to 4 pints per acre
Foliar spray, Spot treatment 3 to 5% solution
Stem base treatment Stem Bases - Spray/paint
undiluted concentrate
Cut Stem Bases - Spray 1:1 solution
triclopyr/water with bark oil
metsulfuron methyl Foliar spray, Broadcast 2 ounces per acre
imazapyr Foliar spray, Broadcast 3 to 4 pints per acre
Chemical
Japanese honeysuckle is largely controlled through the use of herbicides. Metsulfuron methyl can be used as either a broadcast application at a rate of 2 ounces per acre, or as a spot treatment using 2 to 4 ounces per acre. Foliar herbicide applications can also be made using glyphosate at 2 to 3 quarts per acre as a broadcast application or a 2% solution for spot treatments. Triclopyr can be applied as a broadcast application at 3 to 4 pints per acre or as spot treatments using a 3 to 5% solution. Imazapyr can be applied as a broadcast application at 3 to 4 pints per acre. Herbicides should be applied with an appropriate surfactant and ensure complete leaf wetting. Applications made between July and October are most effective as plants are actively growing and herbicide uptake should be optimal. Vines can be cut at the soil surface and the remaining stem bases sprayed or painted with undiluted triclopyr, or sprayed with a 1:1 solution of triclopyr and water. This method may be more labor intensive, but injury to non-target plants will be minimal.

Mechanical
Burning in spring will remove the ground mat of Japanese honeysuckle and sever the vines from the stem bases. Herbicide applications will need to be made to plans that re-grow.

Physical
No physical controls are currently recommended for Japanese honeysuckle.

References


Langeland, K. A. and K. Craddock Burks. 1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. University of Florida publishers. Online resource at http://www.fleppc.org/ID_book.htm accessed [29 December 2007].

Miller, J. H., E. B. Chambliss, C. T. Bargeron. 2004. Invasive Plants of the Thirteen Southern States. Invasive.org: Invasive and Exotic Species of North America. Online resource at http://www.invasive.org/ accessed [29 December 2007].

Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service, 82 pp. Online resource at http://www.invasive.org/eastern/midatlantic/ accessed [29 December 2007].

USDA, NRCS. 2007. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA. Online resource at http://plants.usda.gov accessed [29 December 2007].

More Information


Alien Plant Database
http://www.bugwood.org

Southeast Exotic Plant Pest Council
http://www.se-eppc.org

Southern Weed Science Society
http://www.weedscience.msstate.edu/swss

USDA NRCS PLANTS Database
http://plants.usda.gov/

Contributing Authors


Dr. John D. Madsen, Geosystems Research Institute, Mississippi State University
Ryan M. Wersal, Geosystems Research Institute, Mississippi State University


Contact Info


Dr. Gary N. Ervin
Mississippi State University
Department of Biological Sciences
Box 9627
Mississippi State, MS 39762-9627
Ph. (662)325-1203
gervin@biology.msstate.edu

Geosystems Research Institute
Contact: John D. Madsen, Ph.D.  •  WebMaster