Photographic List Complete List Annual bastard-cabbage Amur corktree Asiatic colubrina Asiatic sand sedge Australian pine Black locust Black swallow-wort Burma reed Bush honeysuckles (exotic) Canada thistle Carrotwood Chinaberry Chinese lespedeza Chinese wisteria Climbing euonymus Cogon grass Common buckthorn Common mullein Common reed English ivy Eurasian watermilfoil Fig buttercup Fire tree Fiveleaf akebia Fountain grass Garlic mustard Goutweed Giant reed Japanese barberry Japanese hop Japanese honeysuckle Japanese knotweed Japanese spiraea Japanese stiltgrass Japanese wisteria Kudzu Leafy spurge Melaleuca Mile-a-minute Multiflora rose Musk thistle Oriental bittersweet Pale swallow-wort Paper mulberry Perennial pepperweed Porcelainberry Princess tree Purple loosestrife Russian-olive Salt cedar Siberian elm Silk tree Smooth cordgrass Spotted knapweed Strawberry guava Tall fescue Tree-of-heaven Velvet tree West Indian marsh grass White poplar Wineberry Yellow Himalayan raspberry Yellow starthistle Aquatics Eurasian watermilfoil Herbaceous Plants Annual bastard-cabbage Asiatic sand sedge Burma reed Canada thistle Cogon grass Chinese lespedeza Common mullein Common reed Eurasian watermilfoil Fig buttercup Fountain grass Garlic mustard Goutweed Giant reed Japanese knotweed Japanese stiltgrass Leafy spurge Musk thistle Perennial pepperweed Purple loosestrife Smooth cordgrass Spotted knapweed Tall fescue West Indian marsh grass Yellow starthistle Shrubs Asiatic colubrina Bush honeysuckles (exotic) Common buckthorn Fire tree Japanese barberry Japanese spiraea Multiflora rose Russian-olive Silk tree Strawberry guava Wineberry Yellow Himalayan raspberry Trees Amur corktree Australian pine Black locust Carrotwood Chinaberry Common buckthorn Melaleuca Paper mulberry Princess tree Salt cedar Siberian elm Silk tree Strawberry guava Tree-of-heaven Velvet tree White poplar Vines Black swallow-wort Chinese wisteria Climbing euonymus English ivy Fiveleaf akebia Japanese honeysuckle Japanese hop Japanese wisteria Kudzu Mile-a-minute Oriental bittersweet Pale swallow-wort Porcelainberry

Lonicera japonica Thunb.
Honeysuckle family (Caprifoliaceae)
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NATIVE RANGE
Japan and Korea 

DESCRIPTION
Japanese honeysuckle is a perennial vine that climbs by twisting its stems around vertical structures, including limbs and trunks of shrubs and small trees. Leaves are oblong to oval, sometimes lobed, have short stalks, and occur in pairs along the stem. In southern and mid-Atlantic states, Japanese honeysuckle often remains evergreen – its leaves remain attached through the winter. In colder northern climates, the leaves may fall off after exposure to prolonged winter temperatures. Flowers are tubular, with five fused petals, white to pink, turning yellow with age, very fragrant, and occur in pairs along the stem at leaf junctures. Stems and leaves are sometimes covered with fine, soft hairs. Japanese honeysuckle blooms from late April through July and sometimes into October. Small black fruits are produced in autumn, each containing 2-3 oval to oblong, dark brown seeds about 1/4 inch across. 

ECOLOGICAL THREAT
In North America, Japanese honeysuckle has few natural enemies which allows it to spread widely and out-compete native plant species. Its evergreen to semi-evergreen nature gives it an added advantage over native species in many areas. Shrubs and young trees can be killed by girdling when vines twist tightly around stems and trunks, cutting off the flow of water through the plant. Dense growths of honeysuckle covering vegetation can gradually kill plants by blocking sunlight from reaching their leaves. Vigorous root competition also helps Japanese honeysuckle spread and displace neighboring native vegetation. 

DISTRIBUTION IN THE UNITED STATES
Japanese honeysuckle occurs across the southern U.S. from California to New England and the Great Lakes region. Escaped populations also occur in Hawaii. Severe winter temperatures and low precipitation may limit its distribution in northern latitudes and in the West, respectively.

HABITAT IN THE UNITED STATES
A ubiquitous invader, Japanese honeysuckle thrives in a wide variety of habitats including fields, forests, wetlands, barrens, and all types of disturbed lands. 

BACKGROUND
Japanese honeysuckle was introduced to the U.S. in the early to mid-1800's as an ornamental plant, for erosion control, and for wildlife forage and cover. Its highly fragrant flowers provide a tiny drop of honey-flavored nectar enjoyed by children. 

BIOLOGY & SPREAD
Growth and spread of Japanese honeysuckle is through vegetative (plant growth) and sexual (seed) means. It produces long vegetative runners that develop roots where stem and leaf junctions (nodes) come in contact with moist soil. Underground stems (rhizomes) help to establish and spread the plant locally. Long distance dispersal is by birds and other wildlife that readily consume the fruits and defecate the seeds at various distances from the parent plant. 

MANAGEMENT OPTIONS
Several effective methods of control are available for Japanese honeysuckle, including chemical and non-chemical, depending on the extent of the infestation and available time and labor.

Manual and Mechanical
For small patches, repeated pulling of entire vines and root systems may be effective. Hand pull seedlings and young plants when the soil is moist, holding low on the stem to remove the whole plant along with its roots. Monitor frequently and remove any new plants. Cut and remove twining vines to prevent them from girdling and killing shrubs and other plants. An effective method for removal of patches of honeysuckle covering the ground is to lift up and hold a portion of the vine mass with a rake and have a chain saw operator cut the stems low to the ground. Mowing large patches of honeysuckle may be useful if repeated regularly but is most effective when combined with herbicide application (see below). Mow at twice a year, first in mid-July and again in mid-September. Plants can also be grubbed out using a pulaski or similar digging tool, taking care to remove all roots and runners. Burning removes above ground vegetation but does not kill the underground rhizomes, which will continue to sprout. In certain situations, tethered goats have been used to remove honeysuckle growth, but must be monitored to prevent their escape to the wild where they would become an added ecological threat.

Chemical
In moderate cold climates, Japanese honeysuckle leaves continue to photosynthesize long after most other plants have lost their leaves. This allows for application of herbicides when many native species are dormant. However, for effective control with herbicides, healthy green leaves must be present at application time and temperatures must be sufficient for plant activity. Several systemic herbicides (e.g., glyphosate and triclopyr) move through the plant to the roots when applied to the leaves or stems and have been used effectively on Japanese honeysuckle.

Following label guidelines, apply a 2.5% rate of glyphosate (e.g., Rodeo® for wetlands; Roundup® for uplands) mixed with water and an appropriate surfactant, to foliage from spring through fall. Alternatively, apply a 2% concentration of triclopyr (e.g., Garlon 3A) plus water to foliage, thoroughly wetting the leaves but not to the point of drip-off. A coarse, low-pressure spray should be used. Repeat applications may be needed. Treatment in the fall, when many non-target plants are going dormant, is best. Also, a 25% glyphosate or triclopyr solution mixed with water can be applied to cut stem surfaces any time of year as long as the ground is not frozen.

Biological
No biological control agents are currently available for Japanese honeysuckle.