Lonicera fragrantissima (fragrant
honeysuckle), L. maackii (Amur honeysuckle), L. morrowii (Morrow's
honeysuckle), L. standishii (Standish's honeysuckle), L. tatarica (Tartarian
honeysuckle), L. xylosteum (European fly honeysuckle), L. X bella (hybrid,
pretty honeysuckle) and possibly others
Honeysuckle
family (Caprifoliaceae)
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NATIVE
RANGE
Eurasia (Japan, China, Korea, Manchuria, Turkey and southern
Russia)
DESCRIPTION
Exotic bush
honeysuckles are upright, generally deciduous shrubs that range from 6 to
15 feet in height. The 1-2 ½ inch, egg-shaped leaves are opposite
along the stem and short-stalked. Older stems are often hollow. Pairs of
fragrant, tubular flowers less than an inch long are borne along the stem
in the leaf axils. Flower color varies from creamy white to pink or crimson
in some varieties of Tartarian honeysuckle. Flowering generally occurs from
early to late spring, but varies for each species and cultivar. The fruits
are red to orange, many-seeded berries. Native bush honeysuckles may be confused
with these exotic species and cultivars, so proper identification is necessary.
Unlike the exotics, most of our native bush honeysuckles have solid stems.
ECOLOGICAL THREAT
Exotic
bush honeysuckles can rapidly invade and overtake a site, forming a dense
shrub layer that crowds and shades out native plant species. They alter habitats
by decreasing light availability, by depleting soil moisture and nutrients,
and possibly by releasing toxic chemicals that prevent other plant species
from growing in the vicinity. Exotic bush honeysuckles may compete with native
bush honeysuckles for pollinators, resulting in reduced seed set for native
species. In addition, the fruits of exotic bush honeysuckles, while abundant
and rich in carbohydrates, do not offer migrating birds the high-fat, nutrient-rich
food sources needed for long flights, that are supplied by native plant species.
DISTRIBUTION IN THE
UNITED STATES
Amur, Tartarian, Morrow's, and pretty honeysuckle
generally range from the central Great Plains to southern New England
and south to Tennessee and North Carolina. The remaining species are
sporadically distributed.
HABITAT IN THE UNITED STATES
Exotic
bush honeysuckles are relatively shade-intolerant and most often occur in
forest edge, abandoned field, pasture, roadsides and other open, upland habitats.
Woodlands, especially those that have been grazed or otherwise disturbed,
may also be invaded by exotic bush honeysuckles. Morrow's honeysuckle and
pretty honeysuckle have the greatest habitat breadth and are capable of invading
bogs, fens, lakeshores, sandplains and other uncommon habitat types.
BACKGROUND
Exotic bush
honeysuckles have been introduced for use as ornamentals, for wildlife cover
and for soil erosion control.
BIOLOGY & SPREAD
Open-grown
exotic bush honeysuckles fruit prolifically and are highly attractive to
birds. In the eastern United States, over twenty species of birds feed on
the persistent fruits and widely disseminate seeds across the landscape.
In established populations, vegetative sprouting also aids in the persistence
of these exotic shrubs.
MANAGEMENT OPTIONS
Mechanical
and chemical methods are the primary means of control of exotic bush honeysuckles.
No biological control agents are currently available for these plants and
any potential agents that might be considered would have to be specific to
the exotic species, for obvious reasons. Hand removal of seedlings or small
plants may be useful for light infestations, but care should be taken not
to disturb the soil any more than necessary. In shaded forest habitats, where
exotic bush honeysuckles tend to be less resilient, repeated clippings to
ground level, during the growing season, may result in high mortality. Clipping
must be repeated at least once yearly because bush honeysuckles that are
cut once and left to grow will often form stands that are more dense and
productive than they were prior to cutting.
Seedlings of exotic bush honeysuckles
can also be controlled by application of a systemic herbicide, like glyphosate
(e.g., Roundup®), at a 1 percent solution, sprayed onto the foliage or applied
by sponge. Well established stands of exotic bush honeysuckles are probably
best managed by cutting the stems to ground level and painting or spraying
the stumps with a slightly higher rate of glyphosate (2-3%).
Prescribed burning has shown
some promise for exotic bush honeysuckles growing in open habitats. In all
instances, control should be initiated prior to the seed dispersal period
(late summer to early autumn) to minimize reinvasion of treated habitats.
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.
CONTACTS
For more information on
the management of exotic bush honeysuckles, please contact:
SUGGESTED ALTERNATIVE PLANTS
Many
native plants make excellent substitutes for exotic bush honeysuckles for home
landscaping and wildlife planting. In the eastern U.S., examples include spicebush
(Lindera benzoin), ink-berry (Ilex glabra), gray dogwood (Cornus racemosa), northern
bayberry (Myrica pensylvanica), red chokecherry (Aronia arbutifolia), and arrowwood
(Viburnum dentatum). These species are readily available through commercial nurseries.
OTHER LINKS
AUTHOR
Charles E. Williams, Clarion
University of Pennsylvania, Clarion, PA
PHOTOGRAPH
Jil M. Swearingen, National
Park Service, Washington, DC
REFERENCES
Luken, J.O. 1990. Forest and
pasture communities respond differently to cutting of exotic Amur honeysuckle.
Restoration and Management Notes 8:122-123.
Nyboer, R. 1992. Vegetation
management guideline: bush honeysuckles. Natural Areas Journal 12:218-219.
The Nature Conservancy. Bush
Honeysuckles: Element Stewardship Abstract. In: Wildland Weeds Management & Research
Program, Weeds on the Web. http://tncweeds.ucdavis.edu/esadocs/loni_spp.html
Williams, C.E. 1994. Bush honeysuckles
(Lonicera spp.). Fact sheet - invasive alien plant species of Virginia. Virginia
Native Plant Society and Virginia Department of Conservation and Recreation,
Richmond, VA.
Plant Conservation
Alliance, Alien Plant Working Group.
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