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Japanese honeysuckle (Lonicera japonica ) An Alien Plant Report Prepared by: Forest Starr, Kim Martz and Lloyd Loope United States Geological Survey Biological Resources Division In cooperation with: American Water Works Association Research Foundation Maui County Board of Water Supply March, 1999

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Page 1: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

Japanese honeysuckle(Lonicera japonica)

An Alien Plant Report

Prepared by:Forest Starr, Kim Martz and Lloyd Loope

United States Geological Survey Biological Resources Division

In cooperation with:American Water Works Association Research Foundation

Maui County Board of Water Supply

March, 1999

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Japanese honeysuckle (Lonicera japonica) 2

Japanese honeysuckle(Lonicera japonica)

What is Japanese honeysuckle? Why is it bad?Japanese honeysuckle is a fast growing vine with glossy green leaves, and fragrant whiteto yellow flowers. Japanese honeysuckle’s twining stems strangle vegetation andanything else in its way.

In Koke’e on Kaua’i, Japanese honeysuckle is spreading and considered by some ashaving the potential to be worse than Banana poka. On Maui, Japanese honeysuckle isbeing used as a landscape plant. Please do not plant Japanese honeysuckle. If you seethis plant in the wild, pull it up and alert the HEAR project.

What should you do if you see this plant?1. Call the Hawaii Ecosystems at Risk (HEAR) project at 572-4418.2. Please do not plant this in your yard.3. Pull out the vine, if possible. Otherwise, cut near the root of the plant, and treat with

an herbicide.4. For more information or additional copies of this flyer, call 572-4418, or websurf to

www.hear.org.

You can help keep Maui no ka oi.

United States Geological SurveyBiological Resources Division

Maui CountyBoard of Water Supply

American Water Works AssociationResearch Foundation

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Japanese honeysuckle (Lonicera japonica) 3

Japanese honeysuckle(Lonicera japonica)

Overview: Japanese honeysuckle is an invasive plant in Hawaii, New Zealand, and theeastern part of North America. It has been widely used in horticulture and is known toescape from gardens into adjacent lands, climbing and smothering other plants in its path.It has been outlawed in both parts of the United States and New Zealand. In Hawaii,even with its invasive history, it is currently sold and planted as ground cover.

Plants in Hawaii were originally thought not to produce fruit, yet viable seed producingplants have been found on Maui in the course of this study. Japanese honeysuckle hasbeen observed spreading vegetatively from gardens into adjacent lands. Its ability toproduce viable seeds allows for long distance dispersal by birds or other animals whichwould allow the plant to invade many more areas currently free of Japanese honeysuckle.Japanese honeysuckle may be just beginning to occupy its potential range.

Potential public involvement: The invasive characteristics and problems associatedwith Japanese honeysuckle have been well documented in the eastern United States andNew Zealand where it has been banned through noxious weed acts. Though, despite theliterature which warns of Japanese honeysuckle’s invasiveness, it is currently beingplanted widely in Hawaii. This information may not be reaching the general public or itdoes not seem like a real threat. Perhaps, only those acutely aware of alien speciesproblems realize the threat Japanese honeysuckle poses to Hawaii’s natural communitiesand watersheds, even with the large amounts of information that has been writtendocumenting its invasiveness. Getting this information out to the general public, tonursery owners, to landscapers, to children in schools, on the television, and on the radioto raise public awareness about the potential harm of Japanese honeysuckle coulddecrease its popularity and decrease the use of the plant in landscaping. Ultimately,making it illegal to possess, as New Zealand and many parts of the United States havedone, would be the best way to minimize further spread.

Common name: Japanese honeysuckle, honekakala (Wagner et al. 1990), Chinesehoneysuckle (Williams and Timmins 1997).

Latin name: Lonicera japonica Thunb.

Taxonomy: In the Caprifoliaceae (honeysuckle) family, Lonicera is a genus of morethan 150 species of shrubs and woody twining climbers. Found in North America andEurasia south to northern Africa, the Philippines, and southwestern Malesia (Wagner etal. 1990).

Description: This vigorous climber grows up to 30 ft (9 m), has glossy, dark greenleaves. Pairs of fragrant white flowers, ageing yellow or sometimes purple tinged(Turner 1997).

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Japanese honeysuckle (Lonicera japonica) 4

Sprawling and twining lianas; young stems pubescent. Leaves ovate, elliptic, oblong, orbroadly lanceolate, blades 3-8 cm long, 1-3.5 cm wide, pubescent, becoming glabrateabove, entire or young lower leaves sometimes lobed. Flowers 2 in axillary cymes,bracts 1-2 cm long, bracteoles suborbicular, ca. 1 mm long; corolla white, turningyellowish or tinged pink, 2-lipped, 2-3 cm long. Berries bluish black, globose, 6-7 mm indiameter (Wagner et al. 1990).

Noxious weed acts: Japanese honeysuckle is not listed on the United States FederalNoxious Weed or Seed Lists. Japanese honeysuckle is not on the Hawaii Noxious WeedList. Japanese honeysuckle is categorized as an exotic weed under the Illinois ExoticWeed Control Act of 1987. As such, commercial sale in Illinois is prohibited (Nyboer1990). In New Zealand, in 1995, Japanese honeysuckle was included on the ForestFriendly list of plants unsuited for planting because of its known weediness (Craw 1994).It is no longer permitted to be sold, propagated, distributed or commercially displayed onthe basis that it is now a Regional Surveillance Plant Pest within the Auckland Region(Auckland Regional Council 1997).

Native range: Native to Asia (Wagner et al. 1990).

Range of invasion: Becoming a serious weed in areas such as eastern North America,New Zealand, and Hawaii. Other areas where Japanese honeysuckle has invaded and isnow widespread include the southern parts of Australia through New South Wales andVictoria, where it is regarded as a very serious threat to native vegetation (Carr et al.1992), and wastelands in parts of Southern Chile (Williams and Timmins 1997).

In Hawaii, the first naturalized collection of Japanese honeysuckle was made in 1951(Wagner et al. 1990). Today, Japanese honeysuckle is widespread in Hawaii (Cronk andFuller 1995). In Hawai’i, it is escaping cultivation in cool, mesic to wet areas in Koke’eState Park, Kaua’i, on O’ahu, East Maui, and scattered localities on Hawai’i (Wagner etal. 1990). On Maui, Japanese honeysuckle has been widely planted, though fewnaturalized or wild populations exist far from original plantings. At most of these wildpopulations, Japanese honeysuckle is moving vegetatively from intentional plantings intoadjacent lands. One wild population is located in a Eucalyptus grove with no signs that ithad been planted. It is not known whether this population has established throughsecondary spread, by bird or other animal, from a nearby planting or whether is an oldhouse site and the Japanese honeysuckle is being persistent. Japanese honeysuckle mayjust be beginning to establish in the wild on Maui.

In New Zealand, Japanese honeysuckle was being sold for horticulture use in 1872(Esler 1988), and was first collected from the wild in 1926. Habitats invaded in NewZealand include shrublands, forest margins, disturbed or secondary forest, wetlandmargins, coastal areas and inshore islands, roadsides, farm hedges, wasteland, roughpasture, modified lowland forest. More vigorous in deeper valley soils (Arulambalam1998). Today, Japanese honeysuckle is widespread in the northern South Island butuncommon in the south part of the island. On the North Island, it is currently listed aswidespread in almost all conservancies (Owen 1997). Typical areas invaded in New

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Japanese honeysuckle (Lonicera japonica) 5

Zealand include the hilly landscapes where there are untrimmed roadsides and unattendedland and associated areas of shrubbery, scrub, and forest remnants (Williams andTimmins 1997). In these areas, Japanese honeysuckle is described as "patchy" anddisplays a distributional pattern similar to other weedy plants whose primary dispersalagent is humans, with secondary spread occurring by birds and other animals. After agradual secondary spread, plants become established then spread vegetatively, and so on(Williams and Timmins 1997). Japanese honeysuckle still has much room to grow inNew Zealand. Making it illegal for humans to disperse the plant may retard its invasionto areas still free of the weed.

In North America, Japanese honeysuckle was introduced in 1806. By the 1860's, it waswidely cultivated. It was first noted from the wild in 1882. The first documentation ofits spread was in 1904, almost one hundred years after its arrival (Andrews 1919;Leatherman 1955). Today, Japanese honeysuckle is widespread throughout the easternUnited States. It is listed as a noxious weed in Illinois and as a pest plant in several othereastern states.

Climate where invading: Cool, mesic to wet areas. Zones 4-10 (Turner 1997).Japanese honeysuckle readily invades open natural communities, often by seed spread bybirds. An aggressive colonizer of successional fields, this vine also will invade matureforest and open woodlands. Forests with either natural or unnatural openings are ofteninvaded by Japanese honeysuckle when birds drop seeds into these light gap areas. Deepshading reduces the amount of invasion (Nyboer 1990). On Kauai, Japanese honeysuckleis escaping and spreading in mesic to wet areas in Koke'e State Park, and near Volcanoand slopes of Hualalai, Hawai'i (Wagner et al. 1990).

On Maui, Japanese honeysuckle can be seen planted widely in a variety of conditions. Ithas been successfully planted from sea level up to 4,200 ft (1,280 m), in dry and wetareas, in shade and full sun, and in a variety of soils. Although, few naturalized or wildpopulations can be found to date on Maui. Most naturalized populations have spreadvegetatively from plantings. Two naturalized populations are located below HaleakalaNational Park, on Crater Road, Kula at 4,000 ft (1,219 m) and 4,200 ft (1,280 m)elevation. The average annual rainfall in this area is about 40 in (Juvik and Juvik 1998).One naturalized population is in full sun, possibly spread vegetatively from a nearbyplanting. The soil is loamy and well drained. The other is in the full shade growing in agrove of Eucalyptus, possibly spread by bird dispersal, as there are no signs of anintentional planting, though this may be an old house site or abandoned water tank,suggesting the plants could have been planted and are persistent. The soil is similar tothat of the first population mentioned. Another naturalized population is at the Waikapugolf course, located at about 800 ft (244 m) elevation, spreading vegetatively into theunmaintained surrounding scrub. Average annual rainfall at this site is about 30 in (Juvikand Juvik 1998).

In North America, Japanese honeysuckle grows up to 5,905 ft (1,800 m) in both open andshaded areas (Williams and Timmins 1997). Climatic limitations to growth in NorthAmerica include frosts in the northern region which causes death of shoots, low

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Japanese honeysuckle (Lonicera japonica) 6

precipitation in the western region, and lack of cold temperatures to break seed dormancyin the south (Leatherman 1955). In New Zealand, plants grow from sea level up to 2,438ft (743 m) (Williams and Timmins 1997). It is one of the few species of plants that aretolerant of pollution from heavy metals and SO2 (Caiazza and Quinn 1980).

Value to humans: Useful as a ground cover or to quickly hide fences and posts. Somevarieties have been used in Chinese medicine since the Tang dynasty in 659 AD (Turner1997). Japanese honeysuckle has been widely cultivated as an ornamental plant, as a roadbank stabilizer, and as food and shelter for wildlife (Handley 1945).

Problems: Japanese honeysuckle is considered a major pest due to its ability tooutcompete and shade out native vegetation (Cacek 1998). This aggressive vineseriously alters or destroys the understory and herbaceous layers of the communities itinvades, including prairies, barrens, glades, flatwoods, savannas, floodplain and uplandforests. Japanese honeysuckle also may alter understory bird populations in forestcommunities (Nyboer 1990). In New Zealand, Japanese honeysuckle infests forests andclimbs over shrublands or low canopy trees, especially on forest margins. Honeysucklemay form a complete blanket over small trees and shrubs. It is becoming an increasinglytroublesome species of shrubland, forest margins, and open roadsides (Arulambalam1998). Japanese honeysuckle is toxic if large quantities are eaten. The vines havesaponic and cyanogenic glycosoides. The fruits have carotenoids (Russell 1997). Effectsfrom eating large quantities of the fruit include vomiting, diarrhea, pupil dilation, coldsweat, rapid heartbeat, respiratory failure, convulsion, and coma (Russell 1197).

Japanese honeysuckle has been known to escape from gardens to become a serious weedelsewhere. In Hawaii, plants were previously thought to not bear fruit (Wagner et al.1990). Wagner et al. (1990) suggest that if fertile strains develop, Japanese honeysucklecould become an extremely serious weed. Recently, fruit has been observed on bothOahu (Wagner et al. 1990) and on Maui. Viable fruit bearing plants allows dispersal bybirds and other animals into areas far from parent plants, in a polka dot pattern, whereasnon-fruit bearing plants can only spread vegetatively, in an amoebae like pattern. Todate, most naturalized populations observed have spread vegetatively from plantings.

Biology and ecology: Japanese honeysuckle climbs and drapes over native vegetation,shading it out. It is capable of completely covering herbaceous and understory plants,and climbing trees to the canopy. The semi-evergreen condition of this honeysuckleallows for growth both prior to and after dormancy of other deciduous plants. Theprolific growth covers and smothers vegetation present including understory shrubs andtrees in forested communities. Vegetative runners are most prolific in the open sun andwill resprout where touching the soil, forming mats of new plants. This honeysuckle willdisplay little growth under moderate shade. In deep shade, runners develop but often dieback. Flowering and seed development are heaviest in open-sun areas. Seedlingestablishment and growth is slow in the first 2 years of development of a newhoneysuckle colony (Nyboer 1990).

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Japanese honeysuckle (Lonicera japonica) 7

Associated animals: Insects known to feed on Japanese honeysuckle in North Americainclude indigenous hawk moths (Sphingidae), wax moths (Gelechiidae) and bumble beeshave been observed extracting pollen from flowers (Williams and Timmins 1997). Awide range of birds are known to feed on fruit in North America from turkeys to smallpasserines (Williams and Timmins 1997). Because of the high water content in the fruit,the seeds pass quickly through birds (Handley 1945). Fruits are also eaten by mammalssuch as deer and possums. Plants respond rapidly to herbivory pressures. However,Japanese honeysuckle spread rapidly after forest reserves in New Zealand were fencedand animals excluded (Williams and Timmins 1997).

Seed viability: According to Wagner et al. (1990), Japanese honeysuckle does notusually produce fruit in Hawaii and if a fertile strain were to develop, it could become anextremely serious weed. Recently, fruit bearing plants have been observed on Oahu(Wagner et al. 1990). Japanese honeysuckle does indeed produce fruit on Maui as well.Several locations of Japanese honeysuckle populations were monitored throughout theyear for phenology data and fruit production. The site descriptions are as follows.Costco, located in Kahului, at sea level has several plantings surrounding the propertyusing Japanese honeysuckle as a ground cover, where it is spreading vegetatively intounmaintained adjacent lots. Waikapu golf course, located in Waikapu, at about 800 ft(244 m) on West Maui, also has several plantings escaping vegetatively into adjacentunmaintained lands. Eddy Tam Park, located in Makawao, at 1,600 ft (488 m) elevation,has Japanese honeysuckle planted as a ground cover on steep banks. Another site is aresidential planting located on Kekaulike Ave., Kula, at 3,700 ft (1,128 m) elevationwhere Japanese honeysuckle is escaping into the adjacent gulch. The last two sites arelocated on Crater Rd., Kula, one at 4,000 ft (1,219 m) and another just above at 4,200 ft(1,280 m). At these two sites, the Japanese honeysuckle seemed slightly different in formand fruit from other populations. We distinguish the two by the latter having a twininghabit, lighter green leaves, and glaucous, greenish-grey fruit. The different form mayprove to be a different species or variety. There are 180 different species of Lonicera andseveral different cultivars of Lonicera japonica. Or, the differences may be attributed toclimatic factors. Further investigation is needed to be sure.

Fruit has been found at all sites checked to date. Fruit was first observed on December15, 1998 on Kekaulike Avenue, Kula. Both immature and mature fruit was observed.Immature fruit was bright green and glossy. Mature fruit was slightly larger, shiny, andblack. Fruit was observed at the Costco site on December 16, 1998. Most fruit foundwere immature, small, shiny, and green. Fruit was abundant and found in clusters offour. Fruit was observed at the 4,000 ft elevation site on December 19, 1998. Most fruitat this site was immature. Both immature and ripe fruit was slightly different in colorthan fruit observed at other sites, appearing a bluish-grey, green color, with a waxy whitefilm (glaucous). Fruit was found at the 4,200 ft Eucalyptus grove site on January 5, 1999.Fruit appeared similar to that found at the 4,000 ft site. Fruit was found at the Eddy Tamsite also on January 5, 1999. Mature fruit was black, and glossy, similar to typical fruitfound. Once fruit was observed on Maui, the next question to answer was whether or notthe seeds in the fruit were viable. Fruit was collected from the 4,000 ft site on January 5,

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Japanese honeysuckle (Lonicera japonica) 8

1999 and from the Kekaulike Ave. site on December 15, 1998 for further comparisonsand germination tests.

Site descriptions:Kekaulike Ave.: Japanese honeysuckle appeared planted on a bank bordering KekaulikeAve. Plants were naturalizing into Keahuaiwi gulch, by Pulehu bridge, along with otherweedy horticulture plants such as Mexican daisy (Erigeron karvinskianus), cape ivy(Senecio mikanioides), Vinca (Vinca spp.), Cotoneaster (Cotoneaster spp.), and butterflybush (Buddleia madagascariensis). This population is representative of commonJapanese honeysuckle.

4,000 ft: Japanese honeysuckle is located on the side of the road, climbing up atelephone pole wire. It may be spreading from a planting, however, this in inconclusive.It is mixed with other weedy plants such as hill raspberry (Rubus niveus), waddle (Acaciamearnsii), olive (Olea europaea cuspidata), and cotoneaster (Cotoneaster spp.). Thisform appears different than common Japanese honeysuckle.

Fruit descriptions:Kekaulike Ave.: Ripe fruits were shiny black, measuring from 5 mm to 10 mm indiameter. 46 fruits were collected. One fruit had a sizeable hole with seed aril and seedsstill intact. Pulp from fruit was greenish and stained paper on which it was a greenishcolor. Another fruit found did not have any seeds or pulp left as if eaten out by something. It is not known what may have eaten the seeds and pulp and left the skin of thefruit.

4,000 ft: The fruit has a thing skin, like that of a grape. It starts out green and turns blackto purple as the fruit ripens. There is a sort of white haze on the surface or skin. Thepulp is green and the seeds are green to brown. The fruit looks smaller than otherJapanese honeysuckle fruit we have observed at Kula, Kahului, and Makawao. We hadalways thought this Japanese honeysuckle looked different, with its viney habit, leavesthat look a little lighter in color, more fruit per axil, and fruit are smaller with a whitesheen. There are also less seeds per fruit. The following table displays these differencesin fruit characteristics.

Site Ave. diameter offruit (mm)

Ave. # seeds perfruit

Ave. diameter ofseed (mm)

Kekaulike Ave. 5.78 5.3 4.384,000 ft 4.79 1.56 3.075

Germination: After seeds were removed from the fruit, 50 random seeds from each sitewere placed in petri dishes, 25 seeds per petri dish, on moist paper towels. Seeds werekept moist by periodically adding bottled water to the petri dishes. Seeds were monitoredfor germination. Germination was defined as sending out a root radicle. Germinationpercentages may increase further over time, however, for the purposes of this report, theexperiment ran for 10 weeks.

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Japanese honeysuckle (Lonicera japonica) 9

Out of the 50 seeds from the Kekaulike site, one germinated, or 2 %, after 10 weeks. Outof the 50 seeds from the 4,000 ft site, 27 germinated, about 54 %, after 10 weeks. Thisraises a few questions. Is the 4,000 ft site population a different strain that is more viableand more likely to invade in Hawaii? Or, are there climatic factors such as high elevationand colder temperatures, which contribute to greater seed viability at this site? Furtherinvestigation is needed to make these conclusions.

Japanese honeysuckle was first found naturalizing in Hawaii in 1951 (Wagner et al.1990). It is a serious weed in eastern North America and New Zealand where it is nowillegal to sell, propagate, distribute, or commercially display it. On Maui, Japanesehoneysuckle is currently being planted widely in many areas where it has spreadvegetatively into adjacent lands. Viable fruit producing plants will allow long distancedispersal to lands currently free of Japanese honeysuckle. Public awareness and furtherdocumentation of its invasive characteristics are needed in order to decrease furtherplantings and spread of Japanese honeysuckle.

Physical control:Cutting: Vines may be chopped just above ground level. Cutting is repeated every twoweeks to deplete nutrient reserves in the roots and prevent resumption of photosynthesis.Cutting does not affect roots, which will continue to grow until their energy and nutrientsupplies are depleted (Cacek 1998). Mowing limits the length of Japanese honeysucklevines, but will increase the number of stems produced (Nyboer 1990).

Flaming: By placing a kerosene torch over leaves on the same schedule as cutting,foliage is wilted and nutrient supplies in the roots are depleted. As with cutting, flamingwill not affect roots.

Burning: Although few quantitative studies occur in the literature, Barden and Matthews(1980) recommend controlled burning. Two annual burns in an experimental plot reducedhoneysuckle crown volume by 80%. Ground cover was reduced by 35%. Fires killedmost aboveground vines, but ground cover was maintained by re- sprouting roots.Burning may be combined with previous flaming, which wilts and dries leaves, providingfuel for the burn (Cacek 1998).

Grubbing: Consists of mechanical removal and destruction of the entire plant, includingthe root. If all root tissue is removed, no regrowth can occur, and repetition is notnecessary. Grubbing is labor intensive and may be locally destructive. Grubbing is mosteffective from fruiting to winter and early spring when plant reserves are lowest.

Grazing: Controlled grazing by goats may serve to reduce honeysuckle crown andground cover densities, but as with controlled burning, re-sprouting roots will regenerateunless nutrient reserves are depleted by continuous grazing pressure.

Regardless of the control method used, care must be taken to prevent re- invasion fromnearby areas, or by seeds transported by birds or other wildlife. Planting the area withfast-growing native vegetation or grasses may prevent recolonization (Cacek 1998).

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Japanese honeysuckle (Lonicera japonica) 10

Chemical control: Mclemore (1981) reports that an acceptable level of control (70%)was reached during a two-year experimental program which used 2 lb/acre of glyphosatein the first year and 6 lb/acre in the second year. Japanese honeysuckle is an evergreen, soit can be treated in the dormant season with less damage to non-target species (Cacek1998). In New Zealand, they cut base of stem and paint with stump paint herbicide mix.Alternatively spray with Escort + Pulse or Tordon Brushkiller herbicide. Cut large vinesat head height and spray below this point. Roundup has been found to be ineffective(Arulambalam 1998). Spray infestations on open ground with Escort. To save treeswhich are growing under or through honeysuckle, cut and paint stems or use TordonGranules (Arulambalam 1998). In temperate areas, because Japanese honeysuckle issemi-evergreen, it will continue to photosynthesize after surrounding deciduousvegetation is dormant. This condition allows managers to detect the amount ofinfestation, and allows for treatment of the infestation with herbicides without damage tothe dormant vegetation (Nyboer 1990).

Glyphosate herbicide (trade name Roundup) is the recommended treatment for thishoneysuckle. A 1.5-2% solution (2-2.6 oz Roundup/gallon water) applied as a spray tothe foliage will effectively eradicate Japanese honeysuckle. Although glyphosate iseffective when used during the growing season, use at this time is not recommended innatural areas because of the potential harm to nontarget plants (Arulambalam 1998).Crossbow, a formulation of triclopyr and 2,4-D, is also a very effective herbicide thatcontrols Japanese honeysuckle. Crossbow should be mixed and applied as a foliar spray.Herbicides that have given poor control results or that are more persistent in theenvironment than other types are picloram, annitrole, aminotriazole, atrazine, dicamba &2,4-D, 2,4_D, DPX 5648, fenac, fenuron, simazine & triclopyr.

Biological control: No natural enemies are reported for this species (Cacek 1998).

Management recommendations: Japanese honeysuckle has a extensive history as aninvasive species, yet is widely planted on Maui in schools, parks and housing complexesand can be bought in most garden shops. Recently, viable fruit have been found, and ithas been seen spreading into wild lands. Perhaps the best strategy for Japanesehoneysuckle is to stop selling it and control infestations adjacent to wild lands. Raisingpublic awareness may help to prevent future plantings, and putting it on the StateNoxious Weed List would provide legal authority for those looking to control the spreadof Japanese honeysuckle.

Key contacts:Maui:USGS/BRD Haleakala Field StationPO Box 369Makawao, HI 96768(808) 572-4472

Kaua’i:

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Japanese honeysuckle (Lonicera japonica) 11

Guy NagaiHawai’i State Department of Agriculture4398A Pualoke St.Lihue, HI 96766-1673(808) 274-3069

REFERENCES & BIBLIOGRAPHY:Andrews, E.F. 1919. The Japanese honeysuckle in the eastern United States. Torreya19: 37-43.

Aukland Regional Council. 1997. Pest Facts #43, Japanese honeysuckle, Lonicerajaponica. Auckland.

Arulambalam, R. 1998. Weeds of New Zealand.http://www.boprc.govt.nz/www/green/WEED63.HTM.

Barden, L. S., and J. F. Matthews. 1980. Change in abundance of honeysuckle(Lonicera japonica) and other ground flora after prescribed burning of a piedmont pineforest. Castanea 45:257-260.

Cacek, T. 1998. The National Park Service Integrated Pest Management Manual.http://www.colostate.edu/Depts/IPMnatparks/exweeds2.html.

Caiazza, N.A., and J.A. Quinn. 1980. Leaf morphology in Arenaria patula and Lonicerajaponica along a pollution gradient. Bulletin of the Torrey Botanical Club 107: 9-18.

Carr, G.W., J.V. Yugovic, and K.E. Robinson. 1992. Environmental weed invasions inVictoria. Department of Conservation and Environment and Ecological HorticulturalPty. Ltd., Melbourne. 78 p.

Craw, J. 1994. Keeping our gardens forest friendly. Forest and Bird 271: 8-12.

Cronk, Q.C., and J. Fuller. 1995. Plant Invaders. Chapman Hall, London. 241 p.

Esler, A.E. 1988. Naturalised plants in urban Auckland: a series of articles from theNew Zealand Journal of botany. DSIR Publishing, Wellington. 618 p.

Handley, C.O. 1945. Japanese honeysuckle in wildlife management. Journal of WildlifeManagement 9: 261-264.

Juvik S.P and J.O. Juvik. 1998. Atlas of Hawai'i. Third edition. Department ofGeography, University of Hawai'i press.

Leatherman, A.D. 1955. Ecological life-history of Lonicera japonica Thunb.Unpublished PhD thesis, University of Tennessee (Library of Congress Card No. Mic.

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Japanese honeysuckle (Lonicera japonica) 12

55-772). 97 p. University Microfilms, Ann Arbor, Michigan (Dissertation Abstracts 15(11): 1987, Publication No. 15,076).

McLemore, B.F. 1982. Comparison of herbicides for controlling hardwoods in pinestands. Proceedings of the 35th annual meeting of the Southern Weed Science Society1982. 195-199.

Nyboer, R. 1990. Vegetation Management Guideline Japanese Honeysuckle.http://www.inhs.uiuc.edu/edu/VGM/jhnysckl.html.

Owen, S.J. 1997. Ecological weeds on conservation land in New Zealand: A database.Department of Conservation, Wellington.

Russell, A. B. 1997. Poisonous Plants of North Carolina.http://russell4.hort.ncsu.edu/poison/Lonicja.htm.

Turner, R. J. Jr., E. Wasson. 1997. Botanica. Random House Australia. NSWAustralia. 1007 pp.

University of Hawaii, Botany Department Web Page. Alien plants of Hawaii. Lonicerajaponica. http://www.botany.hawaii.edu/faculty/cw_smith/lon_jap.htm.

Wagner, W.H., D.R. Herbst, S.H. Sohmer. 1990. Manual of the Flowering Plants ofHawai’i. University of Hawai’i press, Honolulu, Hawai’i.

Williams, P.A., and S.M. Timmins. 1997. Biology and ecology of Japanese honeysuckle(Lonicera japonica) and its impacts in New Zealand. Landcare Research ContractReport: LC 9798/013. D

Page 13: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

Japanese honeysuckle (Lonicera japonica) 13

Japanese honeysuckle fruit and flower

Japanese honeysuckle rooting at the nodes - Kula, Maui

Page 14: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

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Typical use of Japanese honeysuckle in landscaping - Eddie Tam Park, Makawao, Maui

A stand of Japanese honeysuckle escaping into Eucalyptus grove - Kula, Maui

Page 15: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

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Japanese honeysuckle fruit used in germination trials.

Counting Japanese honeysuckle seeds and preparing them for germination trials

Page 16: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

Japanese honeysuckle (Lonicera japonica) 16

Known global distribution of Japanese honeysuckle

Known distribution of Japanese honeysuckle in the state of Hawaii, USA

Page 17: Japanese honeysucklehear.org/species/reports/lonjap_fskm_awwa_report.pdfWhat is Japanese honeysuckle? Why is it bad? Japanese honeysuckle is a fast growing vine with glossy green leaves,

Japanese honeysuckle (Lonicera japonica) 17

Known distribution of Japanese honeysuckle on the island of Maui, state of Hawai'i