Species Management and Control Information

Japanese honeysuckle
Lonicera japonica Thunb.

Source: The following information is taken from a number of sources and those sources are identified at the beginning of the referenced information. The intent of this resource is to provide the user with as much of the information that exists for management and control of this species as is practical. It is important to note that new and improved methods are added regularly which will require you to visit the websites provided for updates on this information. Bibliographies and resources referenced by these sources are not included here, but are included at the websites from which this information was extracted.

READ THIS FIRST!

Before administering any of the following management and control options, it is imperative that you are familiar with the background information provided under the General Management and Control Section.

For additional, and potentially more current, information on management and control of this species, use the Mid-Atlantic Exotic Pest Plant Council (MA-EPPC) listserve or any of the other listserves identified in the Resource - Listserve section of this tutorial. You will find directions for subscribing to the list serve there. The MA-EPPC listserve has an archives feature that saves past discussions (beginning in 1999) about specific species control. These messages are at: http://groups.yahoo.com/group/ma-eppc/messages.

GENERAL MANAGEMENT CONSIDERATIONS:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese Honeysuckle- http://www.nps.gov/plants/alien/fact/loja1.htm - Author: Melissa Bravo - March 5, 2003

Several effective methods of control are available for Japanese honeysuckle, including chemical and non-chemical, depending on the extent of the infestation and available time and labor.

Illinois Vegetation Management Guideline - Japanese honeysuckle (Lonicera japonica) http://www.inhs.uiuc.edu/chf/outreach/VMG/jhnysckl.html - Vol.1, No. 11 - Author: Randy Nyboer - February 6, 1990

Efforts to control Japanese honeysuckle infestations have included the following methods: mowing, grazing, prescribed burning and herbicides. While grazing and mowing reduces the spread of vegetative stems, prescribed burns or a combination of prescribed burns and herbicide spraying appears to be the best way to eradicate this vine.

MANUAL AND MECHANICAL CONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese Honeysuckle- http://www.nps.gov/plants/alien/fact/loja1.htm - Author: Melissa Bravo - March 5, 2003

For small patches, repeated pulling of entire vines and root systems may be effective. Hand pull seedlings and young plants when the soil is moist, holding low on the stem to remove the whole plant along with its roots. Monitor frequently and remove any new plants. Cut and remove twining vines to prevent them from girdling and killing shrubs and other plants. An effective method for removal of patches of honeysuckle covering the ground is to lift up and hold a portion of the vine mass with a rake and have a chain saw operator cut the stems low to the ground. Mowing large patches of honeysuckle may be useful if repeated regularly but is most effective when combined with herbicide application (see below). Mow at twice a year, first in mid-July and again in mid-September. Plants can also be grubbed out using a pulaski or similar digging tool, taking care to remove all roots and runners. Burning removes above ground vegetation but does not kill the underground rhizomes, which will continue to sprout. In certain situations, tethered goats have been used to remove honeysuckle growth, but must be monitored to prevent their escape to the wild where they would become an added ecological threat.

The Nature Conservancy - Species Management Summary (ESA): Japanese honeysuckle - http://tncweeds.ucdavis.edu/esadocs/lonijapo.html - Authors: Victoria Nuzzo - April 1997

Mowing, Discing and Pulling: Removing the above-ground portion of Lonicera japonica reduces current-year growth but does not kill the plant, and generally stimulates dense regrowth. Cut material can take root and should therefore be removed from the site (not practical with most infestations).

Mowing is an ineffective control method, stimulating growth and encouraging formation of dense, albeit shorter, mats. Plants mowed in February formed a dense, 20 cm tall mat within two months, growing from cut stems and rooting from severed runners; by the following November (21 months later) mowed plants were 60 cm high (Stransky 1984). Twice-yearly mowing in Virginia slowed vegetative spread but increased stem density (Williams 1994).

Bush-hogging is an ineffective control, as Lonicera japonica re-invades within one growing season (McLemore 1985).

Discing is apparently an effective control method: McLemore (1985) reported that "control of the honeysuckle was still effective after two years". Discing depth was not indicated. Discing is a highly destructive procedure that destroys native groundlayer species, and may stimulate Lonicera japonica seed bank germination.

Hand-pulling is a time-consuming procedure with limited effectiveness, as the entire plant (roots and shoots) must be removed. Pulling may be a practical method to remove small patches of seedlings.

The Nature Conservancy - Species Management Summary (ESA): Control Comments on the ESA for Japanese honeysuckle http://tncweeds.ucdavis.edu/esadocs/lonijapo.html - Authors: Marc Imlay - February 2002

Marc Imlay (ialm@erols.com, 18 February 2002) has a comment on manual removal: The ESA says:

Hand-pulling is a time-consuming procedure with limited effectiveness, as the entire plant (roots and shoots) must be removed. Pulling may be a practical method to remove small patches of seedlings.

Hand pulling is highly effective over hundreds of acres in our experience. We pull out Japanese honeysuckle by the roots in winter wherever we see it up in the trees, aim the roots upward and tie them in place. The absence of light energy causes the trailing vines to decline precipitously next year. Thus we control 90% of the honeysuckle with 10% of the effort and minimal soil disturbance. We do not pull it out of the trees and watch for native vines (moonseed, trumpet vine, native grape etc.). This method greatly reduces spraying requirements. Use Roundup (glyphosate) or triclopyr in winter or late fall to avoid natives.

PRESCRIBED FIRE:

The Nature Conservancy - Species Management Summary (ESA): Japanese honeysuckle - http://tncweeds.ucdavis.edu/esadocs/lonijapo.html - Authors: Victoria Nuzzo - April 1997

Fire removes above-ground vegetation, and reduces new growth, but does not kill most Lonicera japonica roots, and surviving roots produce new sprouts that return to pre-burn levels of cover within a few years (Oosting and Livingstone 1964). A single spring fire reduced Japanese honeysuckle cover 50% in Illinois (Nyboer 1990). Two sequential fires topkilled Lonicera japonica, reducing crown volume (m3/ha) by 80%, but new growth from root sprouts maintained Lonicera japonica as a dominant groundcover species in North Carolina (Barden and Matthews 1980). In Virginia burning is used to reduce abundance of Lonicera japonica, and inhibit spread for 1-2 growing seasons (Williams 1994). Prescribed burning significantly reduced Lonicera japonica biomass in Tennessee, by 93% when burned in October, and by 59% when burned January - March (Faulkner et al. 1989). Top-killed honeysuckle resprouted in spring (March - April), apparently from roots or runners just below the unburned litter layer. In this situation, follow-up application of 2% glyphosate in spring, 2 - 6 months after burning, appeared to control honeysuckle better on unburned than burned plots, possibly because tall herbaceous vegetation that grew up after the fire on the burned plots intercepted the herbicide before it could reach the shorter honeysuckle resprouts (Faulkner et al. 1989). In Texas, burning in February removed all above ground foliage, but did not kill plants (Stransky 1984). However, burned plants produced fewer and shorter runners than unburned plants, and fire therefore reduced total vegetative growth (Stransky 1984).

Combining fire and herbicides may prove to be more effective than either method by itself if late autumn or winter burns are used to reduce Japanese honeysuckle biomass when most native species are dormant and all resprouts are then treated with a foliar application of glyphosate about a month after they emerge (Johnson, personal communication). Prescribed burns may also be used to help prevent spread of Japanese honeysuckle because seedlings and young plants are most susceptible to fires (Richter, personal communication).

Illinois Vegetation Management Guideline - Japanese honeysuckle (Lonicera japonica) http://www.inhs.uiuc.edu/chf/outreach/VMG/jhnysckl.html - Vol.1, No. 11 - Author: Randy Nyboer - February 6, 1990

In fire-adapted communities, spring prescribed burns greatly reduced Japanese honeysuckle coverage and crown volume. Repeated fires reduced honeysuckle by as much as 50% over a single burn. A previously burned population of honeysuckle will recover after several years if fire is excluded during this time. By reducing honeysuckle coverage with fire, refined herbicide treatments may be applied, if considered necessary, using less chemical.

BIOCONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese Honeysuckle- http://www.nps.gov/plants/alien/fact/loja1.htm - Author: Melissa Bravo - March 5, 2003

No biological control agents are currently (2003) available for Japanese honeysuckle.

The Nature Conservancy - Species Management Summary (ESA): Japanese honeysuckle - http://tncweeds.ucdavis.edu/esadocs/lonijapo.html - Authors: Victoria Nuzzo - April 1997

The only technique that could control Lonicera japonica on a regional scale is biological control, but as of 1997 no formal program had been established. Interestingly, in China, a biocontrol program using Sclerodermus spp. was established to protect Lonicera japonica from the cerambycid Xylotrechus grayi (Tian et al. 1986). Lonicera japonica is utilized by some insects in its native habitat and the U.S. In Sichuan, China, Lonicera japonica growing near cottonfields is an early spring host for aphids that feed on crops later in the growing season (Li and Wen 1988). In North Carolina, the two-spotted spider mite (Tetranychus urticae), an agricultural pest in corn and peanut fields, overwinters on Lonicera japonica growing on field margins (Margolies and Kennedy 1985). Lonicera japonica is also a suitable host for the cicadellid cotton pest (Empoasca biguttula) in Hunan, China (Chen et al. 1987), and may be a host for tobacco leaf curl virus, which was detected in the horticultural variety Lonicera japonica var. aureo-reticulata (Macintosh et al. 1992). The vine is susceptible to honeysuckle latent virus (Brunt et al. 1980), and to tobacco leaf curl bigeminivirus (TLCV) transmitted by whiteflies (MacIntosh et al. 1992).

CHEMICAL CONTROL:

Plant Conservation Alliance - Alien Plant Working Group - Weeds Gone Wild - Factsheet - Japanese Honeysuckle- http://www.nps.gov/plants/alien/fact/loja1.htm - Author: Melissa Bravo - March 5, 2003

In moderate cold climates, Japanese honeysuckle leaves continue to photosynthesize long after most other plants have lost their leaves. This allows for application of herbicides when many native species are dormant. However, for effective control with herbicides, healthy green leaves must be present at application time and temperatures must be sufficient for plant activity. Several systemic herbicides (e.g., glyphosate and triclopyr) move through the plant to the roots when applied to the leaves or stems and have been used effectively on Japanese honeysuckle. Following label guidelines, apply a 2.5% rate of glyphosate (e.g., Rodeo for wetlands; Roundup for uplands) mixed with water and an appropriate surfactant, to foliage from spring through fall. Alternatively, apply a 2% concentration of triclopyr (e.g., Garlon 3A) plus water to foliage, thoroughly wetting the leaves but not to the point of drip-off. A coarse, low-pressure spray should be used. Repeat applications may be needed. Treatment in the fall, when many non-target plants are going dormant, is best. Also, a 25% glyphosate or triclopyr solution mixed with water can be applied to cut stem surfaces any time of year as long as the ground is not frozen.

The Nature Conservancy - Species Management Summary (ESA): Japanese honeysuckle - http://tncweeds.ucdavis.edu/esadocs/lonijapo.html - Authors: Victoria Nuzzo - April 1997

The evergreen and semi-evergreen nature of Lonicera japonica allows application of herbicides when many native species are dormant. Timing of application is critical to effectiveness; in general, applying herbicide shortly after the first killing frost, and before the first hard frost (ca. -4.0oC) is most effective. Herbicide effectiveness can be reduced in areas where large stones or fallen logs protect root crowns from soil-active herbicides (Miller 1985) or where overtopping vegetation intercepts foliar herbicides (Faulkner et al. 1989). Many herbicides produce a short-term reduction in foliar coverage, but do not kill the plant and buds left undamaged by the herbicide can produce new growth that often exceeds growth from untreated plants within a year (Prine and Starr 1971). A foliar application of 1.5% glyphosate shortly after the first frost appears to be the most effective treatment. Treated plants should be re-examined at the end of the second growing season, as plants can recover from herbicide application (McLemore 1981).

GLYPHOSATE (brand names include: Roundup, Rodeo, Accord)

  • October applications of 0.75% and 1.5% v/v glyphosate killed 99% of treated Lonicera japonica within six months in Delaware, and few plants resprouted within 30 months of treatment (Regehr and Frey 1988). The two application rates were equally effective. The same experiment conducted in December resulted in 68% mortality at the lower concentration, and 86% mortality at the higher concentration, and regrowth from buds was much greater than in plants treated in October. The authors concluded that timing of application was critical; applying glyphosate within 2 days of the first frost resulted in very high mortality. After the first frost, higher concentrations of glyphosate were needed to achieve somewhat lower mortality. Defoliation after glyphosate treatment was very slow; only 5-15% of leaves were gone one month after treatment, although 78-90% of stems were dead.
  • A mid-August application of 2.2 kg/ha glyphosate controlled 83% of actively growing Lonicera japonica in North Carolina; control was reduced under drought conditions (Younce and Skroch 1989). Glyphosate (2 lb active ingredient/gal) at 1 to 1.5 gallons/acre controlled "most" Lonicera japonica in Alabama (Miller 1985).
  • In Arkansas, a 6.72 kg active ingredient/ha application resulted in 85% control after one growing season, and 80% control after two growing seasons (McLemore 1981). Lower application rates were less effective two years after treatment.
  • Effectiveness of glyphosate increased linearly with increasing herbicide concentration (0.48-4.8% w/w), but no concentration gave complete control with one application; repeated treatment with 4.8% glyphosate produced complete shoot necrosis in only 50% of plants (Ahrens and Pill 1985)
  • Efficacy of glyphosate was not increased by addition of surfactants (Younce and Skroch 1989, Regehr and Frey 1988).

DICHLORPROP + 2,4-D

  • Dichlorprop mixed with 2,4-D at 3.6 grams active ingredient/liter (1.5% v/v) resulted in 94% mortality when applied within two days of the first frost in October, but only 46% mortality when applied in December. Thirty months after treatment, 14% of stems sprayed in October resprouted, and 75% of stems sprayed in December produced new growth (Regehr and Frey 1988).

2,4-D + PICLORAM (brand names include: Tordon)

  • Picloram is a restricted use soil-active herbicide that is prohibited in California, as it is relatively persistent and subject to leaching.
  • Tordon 101 (4:1 2,4-D amine + picloram, at 1 to 2 gal/acre) "reduced existing honeysuckle to a few surviving crowns" (Miller 1985). Tordon 10K at 50 lb/acre had similar effectiveness (Miller 1985).
  • Tordon 101 at 10 gal acre reduced foliage by 72.5% one year after treatment; a second application of Tordon 101 reduced foliage by a total of 90% one year after re treatment (Prine and Starr 1971)
  • A foliar spray of Tordon 101 at 2.8-8.4 kg/ha gave 84-94% control in a pine stand (McLemore 1982), similar to control provided by amitrole at 2.24 and 4.48 kg/ha. (McLemore 1982).

TEBUTHIURON (brand names include: Spike)

  • Spike 80W (80% tebuthiuron) and Spike 20p (20% tebuthiuron) provided very effective control when applied at 4-5 lbs active ingredient/acre, "resulting in essentially bare plots with yellowing sprigs of vegetation" (Miller 1985).

DICAMBA (brand names include: Banvel, Brushkiller)

  • Banvel 720 (2 lb 2,4-D and 1 lb dicamba) was very effective when applied at 4 gal/acre, but had only partial effectiveness at 3 gallons/acre (Miller 1985).
  • Lower rates of Dicamba, as in Brushkiller 4-41 and 10-51, resulted in limited or no mortality (Miller 1985). In fact, Lonicera japonica growth was stimulated by application of Brushkiller 10-51 (Miller 1985).

SULFOMETURON (brand names include: Oust)

  • A February application of sulfometuron methyl in South Carolina at .25 lb/acre active ingredient, applied when vegetation is less than 30-45 cm high, is recommended for control of Lonicera japonica in loblolly pine stands (Michael 1985).
  • In Georgia, Lonicera japonica was not controlled by a late application of Sulfometuron applied at 3 oz/acre (Withrow et al. 1983)
  • Lonicera japonica was almost completely killed (99% mortality) by a May application of 2 oz metsulfuron-methyl + 0.25% surfactant in central Georgia (Edwards and Gonzalez 1986)

INEFFECTIVE

  • In Illinois, herbicides that are not used by the Department of Conservation due to ineffectiveness or environmental persistence are: picloram; amitrole; aminotriazolel atrazine; dicamba; dicamba + 2,4-D; 2,4-D; DPX 5648; fenac; fenuron; simazine; and triclopyr (brand names for triclopyr include Garlon 3A, Garlon 4 and Brush-B-Gone) (Nyboer 1990).
  • Hexazinone at 2.24 and 6.72 kg Active ingredient/ha was ineffective (McLemore 1981), as was application at 1 or 2 lb active ingredient/acre (Michael 1985). Hexazinone pellets at 8 lb active ingredient/acre reduced Lonicera japonica cover from 100% to 25% cover after three years, while a 2 lb/acre rate resulted in a decrease in cover from 100% to 52% over the same time period (Michael 1984).
  • Oryzalin is apparently ineffective, as it is recommended for use in controlling weeds that threaten Lonicera japonica planted as a groundcover (Bowman 1983)
  • Brushkiller 10-51 at 1.5 gal/acre "encouraged" growth of Lonicera japonica (Miller 1985). Brushkiller 170 resulted in a 45% decrease in foliar cover one year after June treatment (Prine and Starr 1971).
  • June application of 2,4-D (4 lb active ingredient/acre at 10 gal/acre) increased foliar growth of Lonicera japonica by 48% one year after treatment (control plants increased by 0.9%) (Prine and Starr 1971).
  • June application of Banvel resulted in increased foliar growth one year after treatment (Prine and Starr 1971).
  • Triclopyr in both ester and salt formulations (3 and 4lb/gal, respectively) and as an ester combined with 2,4-D (1 and 2lb/gal respectively) failed to control Lonicera japonica one year after treatment (Dreyer 1988). However, in Illinois the latter formulation is reputedly effective (Nyboer 1990).

Nonnative Invasive Plants of Southern Forests: a field guide for identification and Control: Japanese honeysuckle - Gen. Tech. Rep. SRS-62. Asheville, NC, U.S. Department of Agriculture, Forest Service Research Station - http://www.invasive.org/eastern/srs/JH.html - Author: James H. Miller - 2003

Recommended control procedures:

  • Apply Escort* with a surfactant to foliage June to August-either by broadcast spraying 2 ounces per acre in water (0.6 dry ounces per 3-gallon mix) or by spot spraying 2 to 4 ounces per acre in water (0.6 to 1.2 dry ounces per 3-gallon mix).
  • Or, treat foliage with one of the following herbicides in water with a surfactant (July to October or during warm days in early winter) keeping spray away from desirable plants: a glyphosate herbicide as a 2-percent solution (8 ounces per 3-gallon mix) or Garlon 3A or Garlon 4 as a 3- to 5-percent solution (12 to 20 ounces per 3-gallon mix).
  • Or, cut large vines just above the soil surface and immediately treat the freshly cut stem with a glyphosate herbicide or Garlon 3A as a 20-percent solution (2.5 quarts per 3-gallon sprayer) in water with a surfactant July to October (safe to surrounding plants).
  • Prescribed burning in spring will reduce dense ground mats and sever climbing vines for more effective herbicide treatments to re-sprouting vines.

* Nontarget plants may be killed or injured by root uptake.

Illinois Vegetation Management Guideline - Japanese honeysuckle (Lonicera japonica) http://www.inhs.uiuc.edu/chf/outreach/VMG/jhnysckl.html - Vol.1, No. 11 - Author: Randy Nyboer - February 6, 1990

Because Japanese honeysuckle is semi-evergreen, it will continue to photosynthesize after surrounding deciduous vegetation is dormant. This condition allows managers to detect the amount of infestation, and allows for treatment of the infestation with herbicides without damage to the dormant vegetation.
Glyphosate herbicide (tradename Roundup) is the recommended treatment for this honeysuckle. A 1.5-2% solution (2-2.6 oz of Roundup/gallon water) applied as a spray to the foliage will effectively eradicate Japanese honeysuckle. The herbicide should be applied after surrounding vegetation has become dormant in autumn and before a hard freeze (250F). Roundup should be applied carefully by hand sprayer, and spray coverage should be uniform and complete. Do not spray so heavily that herbicide drips off the target species. Retreatment may be necessary for plants that are missed because of dense growth. Although glyphosate is effective when used during the growing season, use at this time is not recommended in natural areas because of the potential harm to nontarget plants. Glyphosate is non-selective, so care should be taken to avoid contacting nontarget species. Nontarget plants will be important in recolonizing the site after Japanese honeysuckle is controlled.
Crossbow, a formulation of triclopyr and 2,4-D, is also a very effective herbicide that controls Japanese honeysuckle. Crossbow should be mixed according to label instructions for foliar application and applied as a foliar spray. It may be applied at dormant periods, like glyphosate, and precautions given above for glyphosate should be followed when using Crossbow. Either herbicide should be applied while backing away from the treated area to avoid walking through the wet herbicide. By law, herbicides only may be applied according to label instructions and by licensed herbicide applicators or operators when working on public properties.

OTHER CONSIDERATIONS:

Illinois Vegetation Management Guideline - Japanese honeysuckle (Lonicera japonica) http://www.inhs.uiuc.edu/chf/outreach/VMG/jhnysckl.html - Vol.1, No. 11 - Author: Randy Nyboer - February 6, 1990

Maintenance control:
In fire-adapted communities, periodic spring burning should control this species.

FAILED OR INEFFECTIVE PRACTICES:
Mowing limits the length of Japanese honeysuckle vines, but will increase the number of stems produced.
Grazing may have the same effects as mowing, but is less predictable due to uneven treatment given by browsing animals.
Herbicides that have given poor control results or that are more persistent in the environment than other types are picloram, annitrole, aminotriazole, atrazine, dicamba, dicamba & 2,4-D, 2,4-D, DPX 5648, fenac, fenuron, simazine & triclopyr.

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