Japan and Korea
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.
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.
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
invader, Japanese honeysuckle thrives in a wide variety of habitats including
fields, forests, wetlands, barrens, and all types of disturbed lands.
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.
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
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.
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.
control agents are currently available for Japanese honeysuckle.
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS.
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
For more information on
the management of Japanese honeysuckle, please contact:
- Lisa Jameson, National Park Service,
Washington, DC, lisa_jameson at nps.gov
- Corey Kudrna, National Park
Service, Washington, DC, corey_kudrna at nps.gov
- Vikki Nuzzo, Cornell University, vnuzzo at earthlink.net
- Ann Rhoads, University
of PA, Morris Arboretum, rhoadsaf at pobox.upenn.edu
- Sue Salmons, National Park
Service, sue_salmons at nps.gov
SUGGESTED ALTERNATIVE PLANTS
that make good substitutes for Japanese honeysuckle include false jasmine
(Gelsemium sempervirens), trumpet honeysuckle (Lonicera sempervirens),
trumpet creeper (Campsis radicans), crossvine (Bignonia capreolata),
native wisteria (Wisteria frutescens), jackman clematis (Clematis
jackmanii), and others. Check with your state native plant society, a
reputable native plant nursery, for recommendations for plants that are appropriate
for your area and conditions.
Melissa A. Bravo, National Park
Service, Roosevelt-Vanderbilt National Historic Sites, Hyde Park, NY
Jil M. Swearingen, National Park
Service, Center for
Urban Ecology, Washington, DC
Sylvan Kaufman, Adkins Arboretum,
Corey Kudrna, National Park Service, Washington, DC
Vikki Nuzzo, Cornell University, Ithaca, NY
Jil M. Swearingen, National Park
Service, Center for
Urban Ecology, Washington, DC
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from the vines Lonicera japonica and Parthenocissus quinquefolia on
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Last updated April 15, 1997.
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Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Japanese Honeysuckle (Lonicera japonica). http://www.invasive.org/weedus/subject.html?sub=3039.
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Virginia Native Plant Society VA
NHP Japanese Honeysuckle Fact Sheet
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