Border privet

Border privet is reported occasionally outside of cultivation throughout the eastern portions of the Great Lakes Basin. It is not reported in Wisconsin, Ontario, or Michigan’s Upper Peninsula. Border privet is reported occasionally throughout the northeastern quarter of the continental U.S. It is challenging to identify privets to species in the field, so it is possible that despite best efforts at verification, some occurrences of border privet have been reported as other privet species and vice versa. Border privet is variably reported as being hardy to Zone 3 or 4. 

Additional invasive species distribution data for specific Great Lakes jurisdictions are available via:

• Midwest Invasive Species Information Network (Michigan)
• iMapInvasives (New York and Pennsylvania)
• EDDMapS Ontario

The seeds of border privet are spread over distance by birds that eat the fruit. It spreads locally by seed and through vegetative growth.

Border privet is most frequent in disturbed areas like roadsides and old fields. However, it has the shade tolerance to establish in higher quality habitats, including floodplain forests and other woodlands, if seed is introduced.

Border privet can form extremely dense thickets due to its wide-spreading branches, high rate of fruit production, fast growth, and short juvenile stage. These thickets out-compete native species for light and other resources.  It should be noted that assessments of the invasiveness of border privet conducted in the Great Lakes region have yielded varying results. It was assessed as highly invasive in Indiana and assessed as not invasive in neighboring Ohio.

Little is known about the horticultural history of border privet in the U.S., though privets in general have been in cultivation for hundreds of years. The most common use of border privet has been as a formal privacy hedge due to its tall stature, dense growth, and ability to withstand heavy pruning. It has also been used extensively along highways (Dirr 1998). It remains available in trade.

No reduced fertility cultivars of border privet are currently commercially available. Research is ongoing at University of Florida to develop sterile cultivars of various privet species (Fetouh et al. 2016). 

Please see our Landscape Alternatives landing page for more information about how the WIGL Collaborative selected alternatives.

^a Bayberry is dioecious (male and female parts occur on different plants), and only female plants form fruit. The recommended cultivar is female, but will need to be paired with a male close by to bear fruit.
^b Height varies by cultivar.

Green = native to part of the Great Lakes Basin
Yellow = native to the United States but not to the Basin
Blue = not native but not invasive

The WIGL Collaborative’s decision trees are designed to help site users, who are perhaps newly discovering that plants that are part of their home landscaping are invasive, prioritize which species should be removed first based on risk to the surrounding environment, economy, and occasionally, to human health. In a perfect world, everybody would remove all invasive plants from their landscaping right away, but in reality, removing mature woody plants involve a hefty investment of time and/or money. These diagrams can help people with multiple woody invasives in their landscaping prioritize to get the most benefit for their efforts.

To learn more about the methodology and information used to develop the decision trees and for helpful hints on how to answer the questions, please see the full report here (PDF).

The following is a brief overview of management techniques shown to be effective on border privet. For more detailed information on how to use these techniques, please visit our Management and Control page. For technical assistance on managing woody invasive species, please get in touch with a local cooperative invasive species management group.

Timing and spread concerns: Catching new infestations quickly and treating them before plants reach maturity is by far the most effective way to control border privet. While this is true of virtually all invasive species, it is especially true of privet due to how difficult it is to control after it is densely established. 

Physical control: Small plants can be hand-pulled from moist soil and larger plants can be dug or pulled using equipment, but the whole root must be removed to prevent regrowth. Privets thrive in disturbed soil, so managers should monitor for and control any new growth from the seed bank in the years following physical removal. Border privet regrows vigorously, so short-duration methods that top-kill plants such as prescribed fire, grazing, and mowing are not unlikely to provide effective control (Munger 2003). 

Chemical control and combined approaches: Foliar treatment during the growing season may be the only practical method for large, dense infestations of border privet, but it may be somewhat less effective than on other shrub species due to the waxy cuticle on border privet leaves. Careful selection of herbicide and surfactants can help improve effectiveness. Cut stump and basal bark treatments are most effective during late summer into fall (Smith et al. 2014). Herbicide should be selected carefully based on site conditions, and label directions read and followed carefully. 

With any treatment it will be necessary to monitor for and treat regrowth in subsequent years. Privet can sprout vigorously if control methods are not fully successful. 

Resources on management of border privet:

• University of Wisconsin Extension
• Ohio State University Extension

• Dirr, MA. 1998. Ligustrum obtusifolium. In: Manual of Woody Landscape Plants, Fifth Edition. Champlain, IL: Stipes Publishing. 560.
• Fetouh, MI, Kareem, A, Knox, GW, Wilson, SB, and Z Deng. 2016. Induction, identification, and characterization of tetraploids in Japanese privet (Ligustrum japonicum). HortScience. 51(11): 1371-1377.
• Maddox, V, Byrd, J. Jr., and B Serviss. 2010. Identification and control of invasive privets (Ligustrum spp.) in the Middle Southern United States. Invasive Plant Science and Management. 3: 482-488. 8/1/2019.
• Munger, GT. 2003. Ligustrum spp.  In: Fire Effects Information System (Online). U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 8/1/2019.
• Smith, A, Boyda, E, and D Apsley. 2014. Controlling Non-Native Invasive Plants in Ohio Forests: Privet (Ligustrum spp.). Ohio State University Extension. 8/1/2019.