Japanese Honeysuckle
How do you identify it?
It is a vine that is semi-evergreen to evergreen with stems that are brown in color. Its leaves are oppositely arranged and oval shaped. Young leaves often have lobes, while older ones have smooth edges. Flowers are trumpet shaped and white or yellow. It also has small black fruits.
Unlike native honeysuckles that grow and spread using tendrils, adhesive disks or aerial roots, Japanese honeysuckle climbs by twining around objects. In this way, this invasive plant forms arbors in forest canopies and dense, sprawling mats on the ground. Vines grow typically six to ten feet long on the ground and occasionally up to 50 feet vertically, and can grow more than 30 feet per year. It can also spread via its berries, the seeds of which are spread by bird and other animal droppings.
Why is it invasive?
Japanese honeysuckle has invaded natural areas. It can be present in forests as well as fields and disturbed areas. It can grow in dense mats and girdle small trees and shrubs that it climbs up. The vine may spread through runners, but seeds can also be dispersed by birds.
How can you manage it?
Hand-pulling may be useful for smaller infestations. Plants should be bagged and removed. Use foliar and cut stump applications of glyphosate or triclopyr for larger infestations. Monitor regularly to ensure that the vines do not resprout. See the NC Forest Service leaflet for more detailed herbicide information, and make sure to follow all label instructions.
Invasive Species Leaflet IS-09 Lonicera japonica (North Carolina Forest Service)
Lonicera japonica thrives in a wide variety of habitats including all types of forests and fields. Dense infestations occur along forest margins, rights-of-way and other disturbed lands. In forests, L. japonica vines spread both horizontally and vertically by climbing up the trunks of small trees and shrubs, which often die from girdling or from dense growth that blocks sunlight from the leaves.
The Invasive Japanese Honeysuckle (Penn State Extension)
Like many invasive species, Japanese honeysuckle (Lonicera japonica) likes to grow along the edge of a disturbance. It prefers full sun but can grow in shade. This plant reproduces by seed or from runners that root at the node. Growth is aggressive, and the plant will climb over other desirable plant material.
Japanese Honeysuckle Lonicera japonica (North Carolina Extension Gardener Plant Toolbox)
Japanese Honeysuckle is a deciduous to semi-evergreen (in the south), naturalized, twining and rampant vine that is difficult to control. It can displace native species by outcompeting native plants for light, space, water and nutrients.
Invasives in Your Woodland: Japanese Honeysuckle (University of Maryland Extension)
Japanese honeysuckle grows in a variety of habitats, including woodlands, wetlands and disturbed areas such as fence rows, roadways and rights-of-way. It is shade-tolerant and often smothers and kills native ground-level vegetation. It can also kill shrubs and saplings by girdling.
Japanese Honeysuckle Field Guide (Missouri Department of Conservation)
Japanese honeysuckle climbs and drapes over native vegetation, shading it out. It can completely cover herbaceous and understory plants and climbs trees to reach the canopy, which may alter understory bird populations. It can become established in forested areas in openings created by fallen trees or by natural features that allow more light into the understory.
Invasive Plant Species Fact Sheet: Japanese Honeysuckle (Indiana Department of Natural Resources)
Japanese honeysuckle damages forest communities by out-competing native vegetation for light and below-ground resources, and by changing forest structure. The vines overtop adjacent vegetation by twining about and completely covering small trees and shrubs. As it becomes established it forms a dense blanket that endangers most shrubs, herbs and trees.