Japanese barberry is a dense,
deciduous, spiny shrub that grows 2 to 8 ft. high. The branches are brown,
deeply grooved, somewhat zig-zag in form and bear a single very sharp spine
at each node. The leaves are small (½ to 1 ½ inches long), oval to spatula-shaped,
green, bluish-green, or dark reddish purple. Flowering occurs from mid-April
to May in the northeastern U.S. Pale yellow flowers about ¼ in (0.6 cm) across
hang in umbrella-shaped clusters of 2-4 flowers each along the length of
the stem. The fruits are bright red berries about 1/3 in (1 cm) long that
are borne on narrow stalks. They mature during late summer and fall and persist
through the winter.
Japanese barberry may be confused with American
barberry (Berberis canadensis), the only native species of barberry
in North America, and common or European barberry (Berberis vulgaris)
which is an introduced, sometimes invasive plant.
forms dense stands in natural habitats including canopy forests, open woodlands,
wetlands, pastures, and meadows and alters soil pH, nitrogen levels, and
biological activity in the soil. Once established, barberry displaces native
plants and reduces wildlife habitat and forage. White-tailed deer apparently
avoid browsing barberry, preferring to feed on native plants, giving barberry
a competitive advantage. In New Jersey, Japanese barberry has been found
to raise soil pH (i.e., make it more basic) and reduce the depth of the litter
layer in forests.
IN THE UNITED STATES
Japanese barberry has been reported to be invasive
in twenty states and the District of Columbia. Due to its ornamental interest,
barberry is still widely propagated and sold by nurseries for landscaping
purposes in many parts of the U.S.
HABITAT IN THE UNITED STATES
is shade tolerant, drought resistant, and adaptable to a variety of open
and wooded habitats, wetlands and disturbed areas. It prefers to grow in
full sun to part shade but will flower and fruit even in heavy shade.
Japanese barberry was introduced
to the U.S. and New England as an ornamental plant in 1875 in the form of
seeds sent from Russia to the Arnold Arboretum in Boston, Massachusetts.
In 1896, barberry shrubs grown from these seeds were planted at the New York
Botanic Garden. Japanese barberry was later promoted as a substitute for
common barberry (Berberis vulgaris) which was planted by settlers
for hedgerows, dye and jam, and later found to be a host for the black stem
grain rust. Because Japanese barberry has been cultivated for ornamental
purposes for many years, a number of cultivars exist.
BIOLOGY & SPREAD
spreads by seed and by vegetative expansion. Barberry produces large numbers
of seeds which have a high germination rate, estimated as high as 90%. Barberry
seed is transported to new locations with the help of birds (e.g., turkey
and ruffed grouse) and small mammals which eat it. Birds frequently disperse
seed while perched on powerlines or on trees at forest edges. Vegetative
spread is through branches touching the ground that can root to form new
plants and root fragments remaining in the soil that can sprout to form new
Do not plant Japanese
barberry. Because it is a prolific seed-producer with a high germination
rate, prevention of seed production should be a management priority. Because
barberry can resprout from root fragments remaining in soil, thorough removal
of root portions is important. Manual control works well but may need to
be combined with chemical in large or persistent infestions.
No biological control
organisms are available for this plant.
Treatments using the systemic
herbicides glyphosate (e.g., Roundup®) and triclopyr (e.g., Garlon) have been
effective in managing Japanese barberry infestations that are too large for
hand pulling. For whole plant treatment, apply a 2% solution of glyphosate
mixed with water and a surfactant. This non-selective herbicide should be
used with care to avoid impacting non-target native plants. Application early
in the season before native vegetation has matured may minimize non-target
impacts. However, application in late summer during fruiting may be most
effective. Triclopyr or glyphosphate may be used on cut stumps or as a basal
bark application in a 25% solution with water, covering the outer 20% of
Because Japanese barberry leafs
out early, it is easy to identify and begin removal efforts in early spring.
Small plants can be pulled by hand, using thick gloves to avoid injury from
the spines. The root system is shallow making it easy to pull plants from
the ground, and it is important to get the entire root system. The key is
to pull when the soil is damp and loose. Young plants can be dug up individually
using a hoe or shovel. Hand pulling and using a shovel to remove plants up
to about 3 ft high is effective if the root system is loosened up around
the primary tap root first before digging out the whole plant.
Mechanical removal using
a hoe or Weed Wrench ® can be very effective and may pose the least threat
to non-target species and the general environment at the site. Tools like
the Weed Wrench ® are helpful for uprooting larger or older shrubs. Shrubs
can also be mowed or cut repeatedly. If time does not allow for complete
removal of barberry plants at a site, mowing or cutting in late summer prior
to seed production is advisable.
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 barberry, please contact:
- Ian Shackleford, Ottawa
National Forest, E6248 U.S.2, Ironwood, MI 49938; (906) 932-1330 x508
- Jessica Murray, Ecological Restoration Coordinator, Berkshire Taconic
Landscape Program, The Nature Conservancy, PO Box 268, Sheffield, MA
01262; (413) 229-0232 x228; jmurray at tnc.org
Many attractive native
shrubs are available that make great substitutes for Japanese barberry. A
few examples include bayberry (Myrica pensylvanica), ink-berry (Ilex
glabra), winterberry (Ilex verticillata), arrow-wood (Viburnum
dentatum), mountain laurel (Kalmia latifolia), ninebark (Physocarpus
opulifolius) and hearts-a-bustin' (Euonymus americana). Please
check with your state native plant nursery for suggestions for plants appropriate
to your area.
Jil M. Swearingen, National Park
Service, Center for Urban Ecology, Washington, DC.
Sylvan Kaufman, Conservation Curator,
Adkins Arboretum, Ridgely, MD.
Jil M. Swearingen, U.S. National Park
Service, Center for Urban Ecology, Washington, DC.
Ehrenfeld, J. G. 1997.
Invasion of deciduous forest preserves in the New York metropolitan region
by Japanese barberry (Berberis thunbergii DC.) Journal of the Torrey
Botanical Society. 124: 210-215.
Ehrenfeld, J. G. 1999. Structure
and dynamics of populations of Japanese barberry (Berberis thunbergii DC.)
in deciduous forests of New Jersey. Biological Invasions 1: 203-213.
Invasive Plant Atlas of New England.
2004. University of Connecticut. http://webapps.lib.uconn.edu/ipane/browsing.cfm?descriptionid=26
Kourtev, P.S., W. Z. Huang, and
J. G. Ehrenfeld. 1999. Differences in earthworm densities and nitrogen dynamics
in soils under exotic and native plant species. Biological Invasions 1: 237-245.
McDonald, Brian (personal communication
with Sylvan Kaufman).
Rhoads, A.F. and T. Blcok. 2002.
Japanese barberry (Berberis thunbergii DC.). Morris Arboretum of the University
of Pennsylvania, Philadelphia PA. 3 pp.
Shackleford, Ian (personal communication
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Silander, J. A. and D. M. Klepeis.
1999. The invasion ecology of Japanese barberry (Berberis thunbergii)
in the New England landscape. Biological Invasions 1: 189-201.
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Japanese Barberry (Berberis thunbergii). http://www.invasive.org/weedus/subject.html?sub=3010.
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Plant Conservation Alliance, Alien Plant Working Group.