User ID
Password
Home  About  Contact
Scientific Name:

Common Name:

Ligustrum japonicum Thunb.
Japanese privet
Family: Oleaceae

USDA Plant Code: LIJA

Habitat: Terrestrial; fields, rights-of-way, open forest

Growth Habit: Perennial Tree, Shrub

Native Environment: Japan, Korea

Introduction



Mature Japanse Privet Plants
Problems Caused
Several species of privet have been introduced in the US since the 1700s, as garden plants and hedges, for which they are very effective. These non-native shrubs, which are difficult to distinguish from one another, include: common privet (L. vulgare L.), glossy privet (L. lucidum Ait. f.), Chinese privet (L. sinense Lour.), and Japanese privet (L. japonicum Thunb.). Japanese privet is thought to have been introduced in 1945. The Ligustrum species easily escape cultivation to invade adjacent areas, where they can form dense monocultural thickets. As a result, they now are established throughout the eastern part of the country.

Regulations
The privets as a group are so widespread that they have been omitted from US and regional noxious species legislation. In the southeast, SC includes Japanese privet as a severe invasion threat, and TN lists this species as a significant threat.

Description


Vegetative Growth
Ligustrum japonicum resembles Chinese privet, L. sinense, the latter of which has smaller and thinner leaves and generally is much more common in the MidSouth.

Japanese privet is an evergreen shrub attaining heights of up to 6m (20ft), with a relatively diffusely spreading canopy, and producing thick, somewhat leathery, oppositely arranged leaves. The twigs are glabrous and pale green, darkening brownish to reddish tinged with maturity. Branches also are oppositely arranged and with brownish gray bark covered with numerous raised, lighter colored lenticels. The leaves tend to be ovate to oblong in outline, their bases rounded and tips blunt or tapering, sometimes exhibiting a short apical spine. Leaves are 5 to 10cm (2-4in) long and 2.5 to 5 cm (1-2 in) wide. Their margins are entire and often yellowish rimmed and slightly rolled under. The upper surfaces of the leaves are a lustrous dark green with 4 to 6 pairs of indistinct veins that protrude slightly from the light green under surfaces.


Leaves and Flowers of Japanese Privet
Flowering
Japanese privet flowers from April to June, producing loosely branching conical clusters of small, white, fragrant, four-petaled flowers at the ends of branches or in axils of sub-terminal branches. Fruit are present from July through February in branched terminal clusters of ovoid drupes, roughly 5 to 12 mm (0.2-0.5in) long and 5mm (0.2in) wide. The fruit are pale green in summer and ripen to blue-black in winter.

Dispersal
Privets grow readily from seed or from root and stump sprouts. These species escape cultivation by movement of seed, which is eaten and subsequently transported by wildlife, especially birds. Despite a reportedly low germination rate (5%-25%), the privets are highly effective dispersers and can be found in abundance in disturbed areas such as field and forest edges and urban and suburban environments.

Spread By
Human spread is largely by planting Japanese privet as an ornamental plant in landscaping.

Habitat


Japanese privet, which is shade tolerant, may occur as single plants or in thickets, frequently occurring in the same habitats as Chinese privet but generally not as abundantly as the latter. Japanese privet will invade both lowland and upland habitats, including floodplains, forests, wetlands and fields, but it usually is more prevalent in lowland habitats, typically at elevations less than 915m (3000ft). All the privets are frequently seen along roadsides and other disturbed areas.

Distribution


United States
Chinese and Japanese privet are found from Texas to Massachusetts, with L. japonicum occurring in a slightly smaller subregion of that area, in about ten states.

MidSouth
In the MidSouth, Japanese privet is very poorly represented in herbaria, as indicated by the USDA PLANTS database (e.g., AL, MS, and TN are shown with collections from 2, 5, and 2 counties, respectively). It most certainly is more widespread than those data would indicate.

IPAMS Surveys:

Control Methods


Chemical Control Options for Japanese Privet
Herbicide Method Rate
glyphosate Foliar spray, Broadcast 2% solution
triclopyr Foliar spray, Broadcast 2% solution
Basal, cut stump, frill 20% solution applied directly to plants
imazapyr Frill or soil application 2 to 6 pints
metsulfuron Foliar spray, Broadcast 1 to 3 ounces
fosamine ammonium Foliar spray, Broadcast 1.5 to 6 gallons
hexazinone Soil application 2 to 4 gallons
2,4-D +
2,4-DP
Foliar spray, Broadcast 1 to 5% solution
Basal, cut stump, frill 3 to 4% solution
imazapyr + glyphosate Foliar spray, cut stump, frill 1 to 2 gallons
Imazapyr + metsulfuron Foliar spray, Broadcast 25 ounces
Biological
No biological controls are currently recommended for Japanese privet.

Chemical
Several herbicides are effective in controlling Japanese privet including 2,4-D, 2,4-DP, glyphosate, imazapyr, triclopyr, metsulfuron, fosamine ammonium, and hexazinone. Herbicide applications can be made directly to plant foliage, at the base of stems, cut stumps, frill applications, and to the soil around Japanese privet. There are several different formulations of the same herbicide available as well as herbicide mixes that can be used to control Japanese privet, so always read herbicide labels prior to applications. Basal herbicide applications can be made to the lower 20 inches of the stem using an appropriate herbicide adjuvant such as a crop oil. Basal applications are more effective on stems 6 inches in diameter or smaller. Cut stump applications are made to stumps immediately after cutting. Frill applications are made by cutting the outer layer of bark and cambium and applying the herbicide to the cut areas.

Mechanical
Hand pulling of young seedlings will prevent future seed production. Cutting or mowing mature plants prior to seed production will prevent seed dispersal and subsequent plant growth. However, any stumps or large shoots that are cut need to be treated with an appropriate herbicide to prevent the regrowth of plants from stumps.

Physical
Shading may prevent seed production, but will not kill the plant.

References


Miller, J. H. 2003. Nonnative invasive plants of southern forests: a field guide for identification and control. Gen. Tech. Rep. SRS–62. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 93 p. Online resource at http://www.invasive.org/eastern/srs/index.html accessed [27 June 2007].

Miller, J. H., E. B. Chambliss, C. T. Bargeron. 2004. Invasive Plants of the Thirteen Southern States. Invasive.org: Invasive and Exotic Species of North America. Online resource at http://www.invasive.org/ accessed [27 June 2007].

Remaley, T. and C. Bargeron. 2003. Southeast Exotic Pest Plant Council Invasive Plant Manual. Southeast Exotic Pest Plant Council. Online resource at http://www.invasive.org/eastern/eppc/introduction.html accessed [27 June 2007].

Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service, 82 pp. Online resource at http://www.invasive.org/eastern/midatlantic/ accessed [27 June 2007].

USDA, NRCS. 2007. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA. Online resource at http://plants.usda.gov accessed [27 June 2007].

More Information


Alien Plant Database
http://www.bugwood.org

Hawaiian Ecosystems at Risk (HEAR) Project
http://www.hear.org/

Southeast Exotic Plant Pest Council
http://www.se-eppc.org

Southern Weed Science Society
http://www.weedscience.msstate.edu/swss

USDA NRCS PLANTS Database
http://plants.usda.gov/


Contributing Authors


Dr. John D. Madsen, Geosystems Research Institute, Mississippi State University
Ryan M. Wersal, Geosystems Research Institute, Mississippi State University


Contact Info


Dr. Gary N. Ervin
Mississippi State University
Department of Biological Sciences
Box 9627
Mississippi State, MS 39762-9627
Ph. (662)325-1203
gervin@biology.msstate.edu

Geosystems Research Institute
Contact: John D. Madsen, Ph.D.  •  WebMaster