Japanese honeysuckle

Japanese honeysuckle has been reported in all Great Lakes jurisdictions except Minnesota. Reports are isolated to occasional with the most frequent sightings near Cambridge, Ontario and in the southwest corner of Michigan. On a continental scale, Japanese honeysuckle is most prevalent in the Southeast and Mid-Atlantic U.S., though it also occurs on in New England and in some western states. USDA reports Japanese honeysuckle as being hardy to a minimum temperature of -13oF (Zone 4). Its distribution may shift north over time as the climate changes.

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

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

The seeds of Japanese honeysuckle are spread over long distances by birds, which eat the fruits. Locally, Japanese honeysuckle spreads vegetatively by rooting at stem nodes (layering) and eventually forming new root crowns (Munger 2002). Once root crowns are established, the offshoot plants can survive independently if severed from the parent.

Japanese honeysuckle most frequently invades open/disturbed habitats such as open woods and forest openings, forest edges, floodplains, rights-of-way, and old fields. However, it can occasionally colonize more densely established forest, persisting for many years in the understory until disturbance creates a gap in the canopy (Munger 2002).

Japanese honeysuckle can form a dense mat-like groundcover, reducing the diversity of native shrubs and forbs and reducing tree recruitment (Munger 2002). Where suitable vertical structures such as trees, fences, utility infrastructure, etc. are present, the vines will climb vertically. Small trees and shrubs can be girdled by climbing Japanese honeysuckle stems (Wisconsin DNR). In addition to ecological impacts, Japanese honeysuckle can damage and slow the growth of timber species.

Native to eastern Asia, Japanese honeysuckle was imported and grown as an ornamental plant in North America starting in the late 1800s (Dirr 1998). It is popular for its showy, fragrant flowers and adaptability to poor soils, and is still in trade today (where not prohibited). It was also planted extensively on public land by a variety of state and federal agencies – particularly on steep highway embankments to prevent erosion and in wildlife areas for cover and forage (Munger 2002).

None.

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

~ = trait is somewhat present but not as pronounced as in check-marked examples

^aA recent study in the Midwest found that invasive bittersweet is sometimes mislabeled as the native species and sold by nurseries. We recommend that shoppers find a reputable nursery (preferably one that specializes in woody and/or native plants) and ask questions to confirm purchase of native bittersweet.
^bAmerican bittersweet is typically dioecious, and a male and female plant will be required to produce fruit. However, the recommended cultivar is capable of self-pollination for fruit production.
^cAlthough native virgin’s bower does have very fragrant flowers, it blooms later in the season than Japanese honeysuckle – late summer to early fall.
^dClimbing hydrangea is technically a clinging vine. While it does climb vertically, it does best on solid surfaces like walls and wooden fences. 

Green = native to part of the Great Lakes Basin
Yellow = native to North America but not to the Great Lakes
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 Japanese honeysuckle. For more detailed information on how to use these techniques, visit our Management and Control page. For local assistance managing woody invasive species, please get in touch with a cooperative invasive species management group or a university extension program.

Timing and spread concerns: Early detection is beneficial when dealing with any invasive species, but especially so for Japanese honeysuckle whose seedling establishment and growth are relatively slow during the initial years of development (Munger 2002). Whenever possible, individual plants should be controlled before they are able to fruit in order to prevent spread. If control is undertaken after plants have fruited, it is best not to remove the plants from the site to avoid spreading seed.

Physical control: Seedlings and young plants can be pulled from moist soil, with care to remove the entire root. Physical removal of mature plants will likely be impractical due to the layering growth habit. Japanese honeysuckle regrows vigorously from cut stems and stumps after injury, so methods that top-kill plants, such as prescribed fire, grazing, and stem cutting, are unlikely to provide effective long-term control and can make the infestation worse over time.

Chemical and combined approaches: Foliar and cut stump applications are effective on this species. Foliar application can be used on plants at the ground level, and should be applied after the first killing frost of the fall to avoid off-target damage to other plants. Foliar treatment may be most effective between the first killing frost but before the first hard freeze when temperatures fall below 27o F (US Forest Service). Climbing vines should be cut close to the base and herbicide applied to the cut surface. This can be done during most of the year, avoiding early spring. Cut stump treatment may not be fully effective if the vines have undergone layering (US Forest Service). In all cases, 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 and new seedlings in subsequent years. 

Resources on management of Japanese honeysuckle:

• University of Wisconsin Extension
• Midwest Invasive Plant Network Control Database
• Illinois Natural History Survey 
• US Forest Service, Northeastern Area State and Private Forestry

• Dirr, MA. 1998. Lonicera japonica. In: Manual of Woody Landscape Plants, Fifth Edition. Champlain, IL: Stipes Publishing. 580.
• Hilty, J. 2017. Japanese honeysuckle In: Illinois Wildflowers. 8/1/2019. 
• Munger, GT. 2002. Lonicera japonica. In: Fire Effects Information System (Online). U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available: https://www.fs.fed.us/database/feis/plants/vine/lonjap/all.html , 8/1/19.
• Sarver, M, Treher, A, Wilson, L, Naczi, R and FB Kuehn. 2008. Japanese honeysuckle and Native twining vine honeysuckles. In: Mistaken Identity? Invasive Plants and Their Native Look-alikes. Delaware Department of Agriculture. 22-23. 
• US Forest Service, Northeastern Area State and Private Forestry. Japanese honeysuckle, Lonicera japonica. In: Forest Invasive Plants Resource Center. 8/1/19.