Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Humulus scandens
(Japanese hop)

Toolbox

Datasheet

Humulus scandens (Japanese hop)

Summary

  • Last modified
  • 07 December 2020
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Humulus scandens
  • Preferred Common Name
  • Japanese hop
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • Humulus scandens is an annual or occasional perennial climbing or trailing vine, native to East Asia. It has been introduced to Europe and North America where it has proved to be invasive, covering open ground or low vegetation, eventuall...

  • Principal Source
  • Draft datasheet under review

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report

Pictures

Top of page
PictureTitleCaptionCopyright
Humulus scandens (Japanese hop); Habit. Raleigh, North Carolina, USA. July 2019.
TitleHabit
CaptionHumulus scandens (Japanese hop); Habit. Raleigh, North Carolina, USA. July 2019.
Copyright©NC Wetlands/via inaturalist.org - CC BY 4.0
Humulus scandens (Japanese hop); Habit. Raleigh, North Carolina, USA. July 2019.
HabitHumulus scandens (Japanese hop); Habit. Raleigh, North Carolina, USA. July 2019.©NC Wetlands/via inaturalist.org - CC BY 4.0
Humulus scandens (Japanese hop); Aggressive habit. Hilltop Cir, Baltimore, MD, USA. November 2018.
TitleAggressive habit
CaptionHumulus scandens (Japanese hop); Aggressive habit. Hilltop Cir, Baltimore, MD, USA. November 2018.
CopyrightPublic Domain - Released by lotteryd via inaturalist.org - CC0 1.0
Humulus scandens (Japanese hop); Aggressive habit. Hilltop Cir, Baltimore, MD, USA. November 2018.
Aggressive habitHumulus scandens (Japanese hop); Aggressive habit. Hilltop Cir, Baltimore, MD, USA. November 2018.Public Domain - Released by lotteryd via inaturalist.org - CC0 1.0
Humulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
TitleFlowers and leaves
CaptionHumulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
Copyright©Krzysztof Ziarnek/via Wikimedia Commons - CC BY-SA 4.0
Humulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
Flowers and leavesHumulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.©Krzysztof Ziarnek/via Wikimedia Commons - CC BY-SA 4.0
Humulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
TitleFlowers and leaves
CaptionHumulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
Copyright©Krzysztof Ziarnek/via Wikimedia Commons - CC BY-SA 4.0
Humulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.
Flowers and leavesHumulus scandens (Japanese hop); Flowers and leaves. Broadwell, Illinois, USA. September 2016.©Krzysztof Ziarnek/via Wikimedia Commons - CC BY-SA 4.0
Humulus scandens (Japanese hop); Flowers. Hsinchu County, Taiwan. September 2018.
TitleFlowers
CaptionHumulus scandens (Japanese hop); Flowers. Hsinchu County, Taiwan. September 2018.
Copyright©傻子/via inaturalist - CC BY-NC 4.0
Humulus scandens (Japanese hop); Flowers. Hsinchu County, Taiwan. September 2018.
FlowersHumulus scandens (Japanese hop); Flowers. Hsinchu County, Taiwan. September 2018.©傻子/via inaturalist - CC BY-NC 4.0
Humulus scandens (Japanese hop); Foliage. Clarke County, Virginia, USA. August 2018.
TitleFoliage
CaptionHumulus scandens (Japanese hop); Foliage. Clarke County, Virginia, USA. August 2018.
Copyright©Stinger/via inaturalist - CC BY 4.0
Humulus scandens (Japanese hop); Foliage. Clarke County, Virginia, USA. August 2018.
FoliageHumulus scandens (Japanese hop); Foliage. Clarke County, Virginia, USA. August 2018.©Stinger/via inaturalist - CC BY 4.0
Humulus scandens (Japanese hop); Paired leaves and short, sharp prickles on the stem. Taiwan. April 2010.
TitleLeaves
CaptionHumulus scandens (Japanese hop); Paired leaves and short, sharp prickles on the stem. Taiwan. April 2010.
Copyright©Shih-Shiuan Kao/via Flickr - CC BY-SA 2.0
Humulus scandens (Japanese hop); Paired leaves and short, sharp prickles on the stem. Taiwan. April 2010.
LeavesHumulus scandens (Japanese hop); Paired leaves and short, sharp prickles on the stem. Taiwan. April 2010.©Shih-Shiuan Kao/via Flickr - CC BY-SA 2.0
Humulus scandens (Japanese hop); Underside of leaf. Hilltop Cir, Baltimore, MD, USA. November 2018.
TitleLeaf
CaptionHumulus scandens (Japanese hop); Underside of leaf. Hilltop Cir, Baltimore, MD, USA. November 2018.
CopyrightPublic Domain - Released by lotteryd via inaturalist.org - CC0 1.0
Humulus scandens (Japanese hop); Underside of leaf. Hilltop Cir, Baltimore, MD, USA. November 2018.
LeafHumulus scandens (Japanese hop); Underside of leaf. Hilltop Cir, Baltimore, MD, USA. November 2018.Public Domain - Released by lotteryd via inaturalist.org - CC0 1.0
Humulus scandens (Japanese hop); Fruit. Shikinomori park, Yokohama, Kanagawa, Japan. October 2019.
TitleFruit
CaptionHumulus scandens (Japanese hop); Fruit. Shikinomori park, Yokohama, Kanagawa, Japan. October 2019.
CopyrightPublic Domain - Released by Takashi Koike/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Fruit. Shikinomori park, Yokohama, Kanagawa, Japan. October 2019.
FruitHumulus scandens (Japanese hop); Fruit. Shikinomori park, Yokohama, Kanagawa, Japan. October 2019.Public Domain - Released by Takashi Koike/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Fruiting bodies. Cook County, Illinois, USA. September 2016.
TitleFruit
CaptionHumulus scandens (Japanese hop); Fruiting bodies. Cook County, Illinois, USA. September 2016.
CopyrightPublic Domain - Released by Evan Barker/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Fruiting bodies. Cook County, Illinois, USA. September 2016.
FruitHumulus scandens (Japanese hop); Fruiting bodies. Cook County, Illinois, USA. September 2016.Public Domain - Released by Evan Barker/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Fruiting body peeled back to show seed. Cook County, Illinois, USA. September 2016.
TitleFruit
CaptionHumulus scandens (Japanese hop); Fruiting body peeled back to show seed. Cook County, Illinois, USA. September 2016.
CopyrightPublic Domain - Released by Evan Barker/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Fruiting body peeled back to show seed. Cook County, Illinois, USA. September 2016.
FruitHumulus scandens (Japanese hop); Fruiting body peeled back to show seed. Cook County, Illinois, USA. September 2016.Public Domain - Released by Evan Barker/via inaturalist - CC0 1.0
Humulus scandens (Japanese hop); Seeds. Provided by ARS Systematic Botany and Mycology Laboratory. China, Manchuria. 2007.
TitleSeeds
CaptionHumulus scandens (Japanese hop); Seeds. Provided by ARS Systematic Botany and Mycology Laboratory. China, Manchuria. 2007.
CopyrightPublic Domain - Released by Carole Ritchie @ USDA-NRCS PLANTS Database/via Wikimedia Commons
Humulus scandens (Japanese hop); Seeds. Provided by ARS Systematic Botany and Mycology Laboratory. China, Manchuria. 2007.
SeedsHumulus scandens (Japanese hop); Seeds. Provided by ARS Systematic Botany and Mycology Laboratory. China, Manchuria. 2007.Public Domain - Released by Carole Ritchie @ USDA-NRCS PLANTS Database/via Wikimedia Commons

Identity

Top of page

Preferred Scientific Name

  • Humulus scandens (Lour.) Merr.

Preferred Common Name

  • Japanese hop

Other Scientific Names

  • Antidesma scandens Lour. (basionym)
  • Humulopsis scandens (Lour.) Grudz.
  • Humulus aculeatus Nutt.
  • Humulus japonicus Siebold & Zucc.
  • Humulus japonicus var. variegatus F. Roem.
  • Humulus scandens var. variegatus (Siebold & Zucc.) Moldenke

International Common Names

  • French: houblon japonais
  • German: Japanischer Hopfen

Local Common Names

  • Brazil: lupulo
  • China: lu cao
  • Hungary: japán komló
  • Italy: luppolo del giappone
  • Japan: kanamugura
  • Sweden: japansk humle

Summary of Invasiveness

Top of page

Humulus scandens is an annual or occasional perennial climbing or trailing vine, native to East Asia. It has been introduced to Europe and North America where it has proved to be invasive, covering open ground or low vegetation, eventually blanketing the land and vegetation, smothering small trees and having significant impacts on native plant biodiversity and ecosystem services especially in riparian areas. The pollen of H. scandens is allergenic. It is not easy to clear and considering that it may be further introduced as an ornamental, it is considered a high risk invasive species in temperate riverside habitats.

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Urticales
  •                         Family: Cannabaceae
  •                             Genus: Humulus
  •                                 Species: Humulus scandens

Notes on Taxonomy and Nomenclature

Top of page

Humulus scandens is one of only three species of Humulus, the others being H. lupulus and H. yunnanensis.  Some authorities list H. japonicus as the accepted name and H. scandens as the synonym. However, both World Flora Online (2020) and EPPO (2020) list H. scandens as the accepted name.

One variety is recorded with variegated foliage (var. variegatus); it was artificially selected in France in the late 1800s and commercially available as an ornamental in the early 1900s.

Description

Top of page

The following description is adapted from Balogh and Dancza (2008)Panke and Renz (2013) and Flora of North America Editorial Committee (2020)

Humulus scandens can vary between 0.5 m and 5.0 m in height, but can reach 9–11 m. Stems are branched, hexangular, twining clockwise on themselves or around other supports. Leaves are opposite, blades light green, cordate, palmately lobed with 5–7(–9) lobes, 5–12 cm long with petioles longer than the blade. Leaf margins are dentate with an acuminate apex; the lower leaf surfaces have pubescent veins, with rigid spinulose hairs, with yellow, sessile, discoid glands. The upper margins of younger leaf blades have stiff cystolithic hairs (i.e. mineral concretions: calcium carbonate or calcium oxalate). Male inflorescences form an erect branched panicle, 15–25 cm, flower anthers without glands. Female inflorescences are ovoid cone-like spikes; bracteole ovateorbiculate, 7–10 mm, pilose, margins densely ciliate-hairy. Infructescences are pendulous, green, cone-like, ovoid to oblong, (1–)1.5–3.0(–4) cm; bracteoles without yellow glands. Achenes are yellow-brown, ovoid-orbicular, inflated to lenticular, 4–5 mm, glandless.

Plant Type

Top of page
Annual
Broadleaved
Herbaceous
Seed / spore propagated
Vine / climber

Distribution

Top of page

Humulus scandens is native to eastern Asia from the Russian Far East in the north, to northern Vietnam. It has been introduced as an ornamental in both Europe and North America where it is becoming an invasive alien species in several regions.

In North America, it is most abundantly established in New England, the mid-Atlantic States and some areas of the Midwest that include Ohio, Indiana, Illinois, Missouri, Iowa, Nebraska and Kansas (NatureServe, 2017). The establishment of H. scandens is more scattered in the northern Midwest (Michigan, Wisconsin, Minnesota, North and South Dakota) and the south-east (Kentucky, Arkansas, Tennessee, North and South Carolina, Georgia and Alabama). It is not yet established in the most southerly states (Florida, Louisiana, Mississippi, Oklahoma and Texas) or west of the Great Plains region. In total, H. scandens has been reported in 31 US states (NatureServe, 2017; Flora of North America Editorial Committee, 2020). In Canada, it is present in Ontario and Quebec (USDA-NRCS, 2019).

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 25 Feb 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Asia

ChinaPresentNative
-AnhuiPresentNative
-BeijingPresent
-FujianPresentNative
-GuangdongPresentNative
-GuangxiPresentNative
-GuizhouPresentNative
-HainanPresentNative
-HebeiPresentNative
-HeilongjiangPresentNative
-HenanPresentNative
-HubeiPresentNative
-HunanPresentNative
-JiangsuPresentNative
-JiangxiPresentNative
-JilinPresentNative
-LiaoningPresentNative
-ShaanxiPresentNative
-ShandongPresentNative
-ShanxiPresentNative
-SichuanPresentNative
-YunnanPresentNative
-ZhejiangPresentNative
JapanPresentNative
-HokkaidoPresentNative
-HonshuPresentNative
-KyushuPresentNative
-Ryukyu IslandsPresentNative
-ShikokuPresentNative
MongoliaPresentNative
North KoreaPresentNative
South KoreaPresentNative
TaiwanPresent
VietnamPresentNative

Europe

AustriaPresent
BelgiumPresentIntroducedListed as a casual alien
CzechiaPresent
FrancePresentIntroducedInvasive
GermanyPresentIntroduced
HungaryPresentIntroducedInvasive
ItalyPresentIntroducedInvasive
RomaniaPresentIntroduced
RussiaPresentNative
-Russian Far EastPresentNative
SerbiaPresentIntroduced
SlovakiaPresentIntroduced
SloveniaPresentIntroduced
SwitzerlandPresentIntroduced
UkrainePresentIntroduced

North America

CanadaPresentIntroduced
-OntarioPresentIntroduced
-QuebecPresentIntroduced
United StatesPresentIntroducedInvasive
-AlabamaPresentIntroduced
-ArkansasPresentIntroduced
-ConnecticutPresentIntroducedInvasive
-DelawarePresentIntroducedInvasive
-District of ColumbiaPresentIntroducedInvasive
-GeorgiaPresentIntroduced
-IllinoisPresentIntroduced
-IndianaPresentIntroducedInvasive
-IowaPresentIntroduced
-KentuckyPresentIntroduced
-MainePresentIntroduced
-MarylandPresentIntroducedInvasive
-MassachusettsPresentIntroduced
-MichiganPresentIntroduced
-MinnesotaPresentIntroduced
-MissouriPresentIntroduced
-NebraskaPresentIntroduced
-New HampshirePresentIntroduced
-New JerseyPresentIntroduced
-New YorkPresentIntroduced
-North CarolinaPresentIntroduced
-North DakotaPresentIntroduced
-OhioPresentIntroduced
-PennsylvaniaPresentIntroducedInvasive
-Rhode IslandPresentIntroduced
-South CarolinaPresentIntroduced
-South DakotaPresentIntroduced
-TennesseePresentIntroducedInvasiveListed as an emerging threat
-VermontPresentIntroduced
-VirginiaPresentIntroducedInvasiveRanked as exhibiting medium level of invasiveness based on its threat to natural communities and native species
-West VirginiaPresentIntroducedInvasiveDesignated as occasionally invasive generally not affecting ecosystem processes but may alter plant community composition by outcompeting one or more native plant species
-WisconsinPresentIntroducedInvasive

History of Introduction and Spread

Top of page

Humulus scandens was first introduced to North America in the late 1800s for use as a tonic in Asian medicine and as an ornamental vine and is still sold for these purposes today (Pannill et al., 2009). It soon escaped and naturalized, first reported in Massachusetts (IPANE, 2005). In Delaware, a few escapes from cultivation were observed in the 1900s.

H. scandens was introduced to France around 1880 with a herbarium specimen from 1881, collected in the Jardin des Plantes, Paris. In 1885, it was presented to the French Horticultural Society, offering greenery at a time of the year when most other plants were dormant. The Friedrich Rohmer company in Quedlinburg (Swaxe-Anhalt, Germany) launched a variegated form (var. variegatus) in 1893 and according to Chevalier (1943), it was widely used for growing over trellises and arbours or sometimes along fences since the 1910s. In 1893, it was found in wastelands along the Cours Journu-Auber road in Bordeaux and in 1947, it was recorded on wastelands at Porte de la Villette in Paris and in Royan, south-west France in 1958. There are records in Alsace documenting the collection of H. scandens at a waste disposal site near Modenheim (EPPO, 2019). More recently, established populations were identified by Brunel and Tison (2005) in a disturbed riparian habitat along the Gardon River near Nîmes in 2004 and further surveys in 2012 found it along 40 km of the same river between Ales and the confluence of the Gardon and Rhone (Pinston, 2013; Mahaut, 2014; Fried et al., 2018) and along the Huveaune River in Marseille (Fried, 2017). In neighbouring Belgium, the species was first recorded as a casual in 1954 (Verloove, 2006).

In Hungary, H. scandens was first collected in 1880 in the Budapest University botanical garden, with the first naturalized occurrence reported in 1894 in Veszto; it had already spread to the environs of Lake Balaton by the 1910s with a current distribution from the northern mountains through the central plains to southern and western Transdanubia (Balogh et al., 2004Balogh and Dancza, 2008).

H. scandens was introduced into Italy as an ornamental in 1885 (Gruppo di Lavoro Specie Esotiche della Regione Piemonte, 2015) and was first recorded as naturalized in Tuscany in 1903 (Saccardo, 1909Arrigoni and Viegi, 2011), with the first record for Lombardy in 1941. It is today considered invasive in Piedmont, Lombardy, Emilia-Romagna (along the Po river) and naturalized in Veneto and Tuscany. It is not recorded on Sicily or Sardinia (Celesti-Grapow et al., 2009).

In Serbia, the first record of H. scandens was in 1999 near Novi Sad on the bank of the Danube-Tisa channel where it was considered at risk of becoming a nuisance invasive plant in wetland habitats (Savić et al., 2008).

Risk of Introduction

Top of page

Humulus scandens was included in the EPPO Alert List in 2007 and subsequently transferred to the List of Invasive Alien Plants in 2012. In 2016, H. scandens was identified as a priority for risk assessment within the requirements of Regulation 1143/2014 (Branquart et al., 2016; Tanner et al., 2017). A subsequent pest risk analysis concluded that H. scandens carries a high phytosanitary risk to the endangered area (EPPO, 2018) and was added to the EPPO A2 List of pests recommended for regulation.

In Italy, H. scandens is included in the Lombardy region blacklist according to the Regional Act No. 10 of March 2008 (Disposizioni per la conservazione della piccola fauna e della flora spontanea) and is also included in the Piedmont region blacklist according to DGR No. 23-2975 of February 2016 (EPPO, 2018).

In the USA, H. scandens is considered a noxious weed; in Connecticut it is categorized as ‘potentially invasive, banned’ while in Massachusetts it is ‘prohibited’ (USDA-NRCS, 2019).

Habitat

Top of page

In both its native and introduced range, H. scandens is a plant of riversides, including loose, bare surfaces of alluvial bars formed by temporary floods (Balogh and Dancza, 2008; Fried et al., 2018), ruderal areas with no dry seasons and hydrophilous tall herb fringe communities of plains and of the montane to alpine levels.

H. scandens invades open disturbed areas such as roadsides and disturbed riverbanks, as well as open woodlands, prairies, herbaceous wet meadows and floodplain forest communities, indicating that it has some shade tolerance (NatureServe, 2017).

Habitat List

Top of page
CategorySub-CategoryHabitatPresenceStatus
Terrestrial ManagedDisturbed areas Present, no further details Harmful (pest or invasive)
Terrestrial ManagedRail / roadsides Present, no further details Harmful (pest or invasive)
Terrestrial ManagedRail / roadsides Present, no further details Natural
Terrestrial Natural / Semi-naturalNatural forests Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalNatural forests Present, no further details Natural
Terrestrial Natural / Semi-naturalNatural grasslands Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalNatural grasslands Present, no further details Natural
Terrestrial Natural / Semi-naturalRiverbanks Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalRiverbanks Present, no further details Natural
Terrestrial Natural / Semi-naturalWetlands Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalWetlands Present, no further details Natural

Biology and Ecology

Top of page

Genetics

The chromosome number of H. scandens is 2= 16 = 14 + XX in female plants and 2= 17 = 14 + XY1Y2 in male plants and sex is determined by the ratio of X chromosomes to autosomes sets (A), with an X:A ratio of 1.0 resulting in a female and a ratio of 0.5 resulting in a male, with the Y chromosomes being dispensable (Alexandrov et al., 2012). The closest relative, the common hop H. lupulus has the same sex determination system as in Japanese hop (X/A) but it differs in the chromosome number (2n = 20 in both female and male plants) and sex chromosome systems (XX/XY).

Reproductive Biology

Flowers are mainly wind pollinated but are frequently visited by honeybees (Balogh and Dancza, 2008).

In its native range in China and North and South Korea, H. scandens flowers from August to October (Park et al., 1999). In the introduced range in Europe, flowering occurs from July to September (Balogh and Dancza, 2008). In Hungary, fruits ripen from the middle of August and seeds remain viable for approximately 3 years (Krauss, 1931). Seeds germinate in early spring, from as early as February in southern France (Pinston, 2013), to mid-April in Hungary (Balogh and Dancza, 2008) which is consistent with observations from the native range with emergence from February to early May, peaking in March with 32-37 seedlings/m2 (Masuda and Washitani, 1990), compared to a mean of 38 seedlings/m2 in the south of France (Fried et al., 2018).

Longevity

H. scandens is a dioecious herbaceous annual or occasional perennial. 

Environmental Requirements

Humulus scandens is principally a temperate species, though the native range extends south to southern China and northern Vietnam thus indicating that it is at least tolerant to warmer, sub-tropical climates. However, no detail on temperature, rainfall and soil preferences were identified.

Climate

Top of page
ClimateStatusDescriptionRemark
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)
Dw - Continental climate with dry winter Tolerated Continental climate with dry winter (Warm average temp. > 10°C, coldest month < 0°C, dry winters)

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Cladosporium Pathogen
Fusarium Pathogen
Oidium Pathogen

Notes on Natural Enemies

Top of page

Zheng et al. (2004) reviewed natural enemies feeding on H. scandens in its native range, including nine fungi known to infect Humulus species, with only one, Pseudocercospora humuli, that may be specific to H. scandens. Of the 27 insects associated with Humulus spp., Epirrhoe sepergressa and Chytonix segregata were reported to have a narrow host range (Zheng et al., 2004) and H. scandens was considered as one of the two main hosts of Apolygus lucorum (Heteroptera: Miridae) (Lu et al., 2012). The granivorous beetle Amara gigantea was observed to feed particularly on H. scandens seed in Japan (Sasakawa, 2010).

A survey of insects on H. scandens in France in 2013-2014 noted Thrips urticae, Oxythrips ulmifoliorum, Dendrothrips saltator [Dendrothrips saltatrix],Paratettix meridionalis, Aphididae and Collembola spp., as well as eggs of Melanostoma sp., larvae of Altica sp., Chromatomyia horticola and Carabidae, Chrysomelidae, Cicadellidae, Theridiidae and Thripidae (EPPO, 2019). Young leaves were also observed being eaten by snails including Cernuella virgata and Oxyloma elegans. Zonate leaf spot caused by Hinomyces moricola was first reported on H. scandens in wetlands in Yeongdong, Korea (Cho et al., 2013). Initial symptoms included greyish-green to greyish-brown spots without border lines; as the lesions enlarged, they coalesced leading to leaf blight.

Cuscuta campestris is an alien plant parasite that is also frequently observed on H. scandens in riparian habitats, where it is also attacked by fungi including Oidium sp., Fusarium sp. and Cladosporium sp.. H. scandens is also a host of the aphid Phorodon humuli (EPPO, 2019).

Means of Movement and Dispersal

Top of page

Humulus scandens was introduced into Europe as an ornamental species (Chevalier, 1943; Balogh and Dancza, 2008). Though currently this species is not widely sold in major garden centre chains, seeds are still available in more specialized nurseries and can also be ordered through the Internet; according to forums and websites, the plant is still widely used and exchanged by gardeners and horticulturists (EPPO, 2019).

Pathway Vectors

Top of page
VectorNotesLong DistanceLocalReferences
Mail Yes Yes

Impact Summary

Top of page
CategoryImpact
Cultural/amenity Negative
Economic/livelihood Negative
Environment (generally) Negative
Human health Negative

Impact

Top of page

In its native range in Japan, H. scandens is considered a weedy vine in riparian and floodplain habitats where it outcompetes native plants such as Miscanthus sacchariflorus and Phragmites australis and decreases the diversity of native plant communities (Ohtsuka and Nemoto, 1997; Ju et al., 2006).

In the USA, H. scandens forms dense stands that outcompete existing vegetation, especially in moist areas (NatureServe, 2017). It is capable of climbing trees and other nearby vegetation, sometimes resulting in shading, girdling and occasionally even death if trees are small and can also become the dominant understorey plant (NatureServe, 2017). H. scandens invades open disturbed areas such as roadsides and disturbed riverbanks, as well as open woodlands, prairies, herbaceous wet meadows and floodplain forest communities, indicating that it has some shade tolerance (NatureServe, 2017). In Hungary, H. scandens can also invade undisturbed ecological corridors where it outcompetes native species and is considered a transformer species that threatens plant communities dominated by Phragmites, Salix and Filipendulo-Petasition alliance vegetation (Balogh and Dancza, 2008). In France, H. scandens has a negative impact on native plant communities by reducing species richness and modifying species composition (Mahaut, 2014), especially on early emerging spring species such as Atriplex prostrata, Mentha suaveolens, Persicaria hydropiper and Veronica anagallis-aquatica; dense mats of H. scandens can persist along riverbanks for several years, reducing ecosystem functioning.

In the USA, H. scandens reduces light levels when it covers existing dominant vegetation (NatureServe, 2017) and by smothering tree saplings in riparian areas it can modify the dynamics of natural vegetation succession (NatureServe, 2017). H. scandens negatively affects cultural ecosystem services where dense cover obstructs river access and recreational activities.

In its native range, humans have allergic reactions to H. scandens pollen. Aerobiological studies in China and South Korea showed that H. scandens pollen counts are even higher than those of both common mugwort (Artemisia vulgaris) and ragweed (Ambrosia artemisiifolia), two species with very high pollen counts and account for about 18% of total pollen during the pollination period (Park et al., 1999; Song et al., 2012; Song, 2017).

H. scandens vines are covered with hooked hairs which makes working with them painful and can lead to dermatitis and blistering may occur, so it is best to use gloves, etc. when working with these plants. (Meyers-Rice, 2014).

Risk and Impact Factors

Top of page
Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Highly mobile locally
  • Fast growing
  • Has high reproductive potential
Impact outcomes
  • Ecosystem change/ habitat alteration
  • Modification of nutrient regime
  • Modification of successional patterns
  • Negatively impacts human health
  • Reduced native biodiversity
  • Threat to/ loss of native species
Impact mechanisms
  • Causes allergic responses
  • Competition - monopolizing resources
  • Competition - smothering
  • Rapid growth
Likelihood of entry/control
  • Highly likely to be transported internationally deliberately
  • Difficult to identify/detect as a commodity contaminant

Uses

Top of page

In its native range, the whole plant is used medicinally and the seed oil is used to make soap (Flora of China Editorial Committee, 2020). No other information is known concerning the plant’s economic benefits. It does not have the lupulin glands that produce the bitter substance used to flavour beer and which are present in H. lupulus.

In Europe, H. scandens does not have any economic importance apart from limited use as an ornamental and being kept in many botanic gardens. This species is sold as an ornamental plant in Europe and also in North America where mostly female plants are for sale.

In the USA, H. scandens is known to gardeners as an attractive annual (or occasionally weakly perennial) vine with variegated forms being common (Meyers-Rice, 2014).

Uses List

Top of page

Medicinal, pharmaceutical

  • Traditional/folklore

Ornamental

  • garden plant

Similarities to Other Species/Conditions

Top of page

Humulus scandens is closely related to the commercial hop (H. lupulus), but differs in chromosome number in both male and female plants and can be readily differentiated using molecular markers (Alexandrov et al., 2012).

Prevention and Control

Top of page

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Physical/Mechanical Control

Humulus scandens can be hand-pulled any time of the year, with the most effective time being late spring or early summer before seed formation. If the vine has climbed a tree, below-ground removal only is required. If seeds are present during removal, avoid movement off-site unless material can be transported without spreading seed. Three years of removal is typically needed to eradicate an infestation and exhaust the seed bank (Meyers-Rice, 2014). Mowing or cutting many times a year can control new populations after 3 years, but well-established populations will only be suppressed. The use of a mower that bags cut material is recommended or the cut material should be raked and bagged after mowing. Cut material should be disposed off in a landfill or burnt to avoid spreading seeds to other areas.

Meyers-Rice (2014) recommends that if H. scandens is growing as an annual, attempts should be made to remove as much of the rootstock as possible as re-sprouts could occur from both the rootstock and the leafy portions of the plant and pulled plants should be removed or left where they cannot re-root. If the plants are growing as perennials, they should be pulled either during May-June when the rootstock is most exhausted and small, or just prior to flowering when the rootstock should be plump and robust. Burning the plants would be unwise since the fire might be carried into the crowns of trees.

Biological Control

There are no known biological control agents for H. scandens. However, the US Forest Service has been investigating natural enemies of plants of Asian origin that are invasive in the USA (EPPO, 2019) and have identified two moths (Epirrhoe sepergressa and Chytonix segregata) and one fungus (Pseudocercospora humuli) as potential natural enemies and will continue research on those species. However, in view of the commercial value of the very closely related common hop (H. lupulus) used in the manufacture of beer, it would appear very unlikely that any species-specific agent could be found and failing that, that any release would be authorized noting the potential impacts.

Chemical Control

Chemical control using herbicides has been shown to be effective at controlling infestations of H. scandens (Panke and Renz, 2013). However, any chemical application near water bodies may require specific permission from national regulatory authorities.

Meyers-Rice (2014) noted that when farmers in the USA wish to eradicate H. lupulus, they spray with glyphosate and this should also be effective against H. japonicus. If the plant is behaving as an annual, spot applications of glyphosate any time during the year (prior to flowering) should damage the plant enough so it will not be able to flower and set seed. If it is growing as a perennial, the best time to apply glyphosate would be when the rootstock is most rapidly accumulating carbohydrates (July-September), whereas applying glyphosate earlier in the year would not be effective as it would not be translocated into the rootstock.

The cost of control in France was estimated as follows: (i) manual control by hand pulling at €10.4/m2, (ii) mechanical control by grinding at €1.1/m2 and (iii) mechanical control by mowing the cheapest at €0.6/m2 (EPPO, 2019). Based on the area (20,000-30,000 m2) where the species was recorded between 2012 and 2015 on the Gardon River and with an average cost of €6/m2 for management and supplementary costs including travel and surveying time and miscellaneous and unexpected expenses, the estimated cost of managing all populations was €580,000 over 2 years.

References

Top of page

Alexandrov OS, Divashuk MG, Yakovin NA, Karlov GI, 2012. Sex chromosome differentiation in Humulus japonicus Siebold & Zuccarini, 1846 (Cannabaceae) revealed by fluorescence in situ hybridization of subtelomeric repeat. Comparative Cytogenetics, 6(3), 239-247.

Arrigoni PV, Viegi L, 2011. (La flora vascolare esotica spontaneizzata della Toscana). In: La flora vascolare esotica spontaneizzata della Toscana [ed. by Arrigoni PV, Viegi L]. Firenze, Italy: Regione Toscana Direzione generale politiche territoriali, ambientali e per la mobilità.216 pp. https://www.regione.toscana.it/documents/10180/320308/La%20flora%20vascolare%20esotica%20spontaneizzata%20della%20Toscana/acd32225-2909-4d0b-a1ba-80f89d68a3f7

Balogh L, Dancza I, Kiraly G , 2004. Actual list of neophytes in Hungary and their classification according to their success. (A magyarországi neofitonok időszerű jegyzéke és besorolásuk inváziós szempontból). In: Biológiai inváziók Magyarországon: Özönnövények (Biological invasions in Hungary: invasive plants), [ed. by Mihály, B, Botta-Dukát, Z]. Budapest, Hungary: TermészetBÚVÁR Alapítvány Kiadó. 61-92.

Balogh, L., Dancza, I., 2008. Humulus japonicus, an emerging invader in Hungary. In: Plant invasions: human perception, ecological impacts and management, [ed. by Tokarska-Guzik, B., Brock, J. H., Brundu, G., Child, L., Daehler, C. C., Pyšek, P.]. Leiden, Netherlands: Backhuys Publishers. 73-91.

Branquart, E., Brundu, G., Buholzer, S., Chapman, D., Ehret, P., Fried, G., Starfinger, U., Valkenburg, J. van, Tanner, R., 2016. A prioritization process for invasive alien plant species incorporating the requirements of EU Regulation no. 1143/2014. Bulletin OEPP/EPPO Bulletin, 46(3), 603-617. doi: 10.1111/epp.12336

Brunel S, Tison JM, 2005. Compilation of available invasive plant lists in the Mediterranean Basin and comparison with other Mediterranean regions of the world. Draft May 2005, UICN, CBNMP.

Celesti-Grapow, L., Alessandrini, A., Arrigoni, P. V., Banfi, E., Bernardo, L., Bovio, M., Brundu, G., Cagiotti, M. R., Camarda, I., Carli, E., Conti, F., Fascetti, S., Galasso, G., Gubellini, L., Valva, V. la, Lucchese, F., Marchiori, S., Mazzola, P., Peccenini, S., Poldini, L., Pretto, F., Prosser, F., Siniscalco, C., Villani, M. C., Viegi, L., Wilhalm, T. (et al), 2009. Inventory of the non-native flora of Italy. Plant Biosystems, 143(2), 386-430. doi: 10.1080/11263500902722824

Chevalier, A., 1943. Notes on the hop. (Notes sur le houblon). Revue de Botanique Appliquee, 23, 225-42.

Cho, S. E., Park, J. H., Hong, S. H., Shin, H. D., 2013. First report of zonate leaf spot caused by Hinomyces moricola on Japanese hop in Korea. Plant Disease, 97(8), 1117-1118. doi: 10.1094/PDIS-01-13-0021-PDN

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

EPPO, 2018. Pest risk analysis for Humulus scandens. In: Pest risk analysis for Humulus scandens Paris, France: European and Mediterranean Plant Protection Organization (EPPO)EPPO.68 pp. https://pra.eppo.int/pra/5f9d091b-921b-460b-8ab9-5ec424777d64

EPPO, 2019. EPPO Global database. In: EPPO Global database Paris, France: EPPO.https://gd.eppo.int/

EPPO, 2020. EPPO Global database. In: EPPO Global database Paris, France: EPPO.

Flora of China Editorial Committee, 2020. Flora of China. In: Flora of China St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria.http://www.efloras.org/flora_page.aspx?flora_id=2

Flora of North America Editorial Committee, 2020. Flora of North America North of Mexico. In: Flora of North America North of Mexico St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria.http://www.efloras.org/flora_page.aspx?flora_id=1

Fried G, 2017. Guide des plantes invasives, Paris, France: Belin.302 pp.

Fried, G., Mahaut, L., Pinston, A., Carboni, M., 2018. Abiotic constraints and biotic resistance control the establishment success and abundance of invasive Humulus japonicus in riparian habitats. Biological Invasions, 20(2), 315-331. doi: 10.1007/s10530-017-1533-y

Gruppo di Lavoro Specie Esotiche della Regione Piemonte, 2015. (Scheda monografica Humulus japonicus). Torino, Italy: Gruppo di Lavoro Specie Esotiche della Regione Piemonte.https://www.regione.piemonte.it/web/sites/default/files/media/documenti/2020-11/humulus_japonicus_-_scheda_semplificata.pdf

IPANE, 2005. Humulus japonicus (Japanese hops). In: Invasive plant atlas of New England , USA: www.invasive.org/weedcd/pdfs/ipane/Humulusjaponicus.pdf

Ju EJ, Kim JG, Lee YW, Lee BA, Kim H, Nam JM, Kang HJ, 2006. Growth rate and nutrient content changes of Humulus japonicus. Journal of Ecology and Field Biology, 29(5), 461-467. doi: 10.5141/JEFB.2006.29.5.461

Krauss O, 1931. (Humulus L., Hopfen). In: Pareys Blumengärtnerei, [ed. by Bonstedt C]. Berlin, Germany: Verlag Paul Parey. 498-499.

Lu YanHui, Jiao ZhenBiao, Wu KongMing, 2012. Early season host plants of Apolygus lucorum (Heteroptera: Miridae) in Northern China. Journal of Economic Entomology, 105(5), 1603-1611. doi: 10.1603/EC12003

Mahaut L, 2014. (Le houblon du Japon (Humulus japonicus Siebold. & Zucc.), une espece locomotrice ou une simple passagere du train des changements? MSc thesis). France: University of Montpellier. 44 pp.

Masuda, M., Washitani, I., 1990. A comparative ecology of the seasonal schedules for 'reproduction by seeds' in a moist tall grassland community. Functional Ecology, 4(2), 169-182. doi: 10.2307/2389336

Meyers-Rice B, 2014. Weed notes: Humulus japonicus. USA: https://wiki.bugwood.org/Humulus_japonicus

NatureServe, 2017. NatureServe Explorer: An online encyclopedia of life. Version 7.1. In: NatureServe Explorer: An online encyclopedia of life. Version 7.1 Arlington, Virginia, USA: NatureServe.http://explorer.natureserve.org/index.htm

Ohtsuka, T., Nemoto, M., 1997. Effect of soil eutrophication on weedy riparian communities around agricultural areas. Journal of Weed Science and Technology, 42(2), 107-114.

Panke, B, Renz, M, 2013. Management of invasive plants in Wisconsin: Japanese hop (Humulus japonicus) (A3924-26). Madison, USA: Cooperative Extension, University of Wisconsin-Extension.4 pp. https://cdn.shopify.com/s/files/1/0145/8808/4272/files/A3924-26.pdf

Pannill PD, Cook A, Hairston‐Strang A, Swearingen JM, 2009. Fact Sheet: Humulus japonicus. In: Alien plant invaders of natural areas , USA: Plant Conservation Alliance, Alien Plant Working Group.https://www.invasive.org/alien/fact/huja1.htm

Park, J. W., Ko, S. H., Kim, C. W., Jeoung, B. J., Hong, C. S., 1999. Identification and characterization of the major allergen of the Humulus japonicus pollen. Clinical and Experimental Allergy, 29(8), 1080-1086. doi: 10.1046/j.1365-2222.1999.00615.x

Pinston A, 2013. (Etude de la plasticite ecologique d’une plante invasive, Humulus japonicus. MSc thesis). Dijon, France: University of Bourgogne.

Saccardo PA, 1909. Cronologia della flora italiana, Padova, Italy: Tipografia del Seminario.

Sasakawa, K., 2010. Field observations of climbing behavior and seed predation by adult ground beetles (Coleoptera: Carabidae) in a lowland area of the temperate zone. Environmental Entomology, 39(5), 1554-1560. doi: 10.1603/EN10097

Savić D, Anačkov G, Boža P, 2008. New chorological data for flora of the Pannonian region of Serbia. Central European Journal of Biology, 3(4), 461-470.

Song UhRam, 2017. Temperature-dependent performance of competitive native and alien invasive plant species. Acta Oecologica, 84, 8-14. doi: 10.1016/j.actao.2017.08.001

Song UhRam, Mun SaeRomi, Ho ChangHoi, Lee EunJu, 2012. Responses of two invasive plants under various microclimate conditions in the Seoul Metropolitan Region. Environmental Management, 49(6), 1238-1246. doi: 10.1007/s00267-012-9852-3

Tanner, R., Branquart, E., Brundu, G., Buholzer, S., Chapman, D., Ehret, P., Fried, G., Starfinger, U., Valkenburg, J. van, 2017. The prioritisation of a short list of alien plants for risk analysis within the framework of the Regulation (EU) No. 1143/2014. NeoBiota, (No.35), 87-118. doi: 10.3897/neobiota.35.12366

USDA-NRCS, 2019. The PLANTS Database. In: The PLANTS Database Greensboro, North Carolina, USA: National Plant Data Team.https://plants.sc.egov.usda.gov

Verloove, F., 2006. Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica, 39, 89 pp.

World Flora Online, 2020. World Flora Online. In: World Flora Online : World Flora Online Consortium.http://www.worldfloraonline.org

Zheng, H., Wu, Y., Ding, J., Binion, D., Fu, W., Reardon, R., 2004. Invasive Plants of Asian Origin Established in the United States and their Natural Enemies, USA: USDA Forest Service.

Distribution References

Balogh L, Dancza I, 2008. Humulus japonicus, an emerging invader in Hungary. In: Plant invasions: human perception, ecological impacts and management. [ed. by Tokarska-Guzik B, Brock J H, Brundu G, Child L, Daehler C C, Pyšek P]. Leiden, Netherlands: Backhuys Publishers. 73-91.

Celesti-Grapow L, Alessandrini A, Arrigoni P V, Banfi E, Bernardo L, Bovio M, Brundu G, Cagiotti M R, Camarda I, Carli E, Conti F, Fascetti S, Galasso G, Gubellini L, Valva V la, Lucchese F, Marchiori S, Mazzola P, Peccenini S, Poldini L, Pretto F, Prosser F, Siniscalco C, Villani M C, Viegi L, Wilhalm T (et al), 2009. Inventory of the non-native flora of Italy. Plant Biosystems. 143 (2), 386-430. DOI:10.1080/11263500902722824

Cho S E, Park J H, Hong S H, Shin H D, 2013. First report of zonate leaf spot caused by Hinomyces moricola on Japanese hop in Korea. Plant Disease. 97 (8), 1117-1118. DOI:10.1094/PDIS-01-13-0021-PDN

EPPO, 2018. Pest risk analysis for Humulus scandens. In: Pest risk analysis for Humulus scandens, Paris, France: European and Mediterranean Plant Protection Organization (EPPO)EPPO. 68 pp. https://pra.eppo.int/pra/5f9d091b-921b-460b-8ab9-5ec424777d64

EPPO, 2019. EPPO Global database. In: EPPO Global database. Paris, France: EPPO. https://gd.eppo.int/

EPPO, 2020. EPPO Global database. In: EPPO Global database, Paris, France: EPPO. https://gd.eppo.int/

Fried G, Mahaut L, Pinston A, Carboni M, 2018. Abiotic constraints and biotic resistance control the establishment success and abundance of invasive Humulus japonicus in riparian habitats. Biological Invasions. 20 (2), 315-331. DOI:10.1007/s10530-017-1533-y

Heffernan K, Engle E, Richardson C, 2014. Virginia invasive plant species list., Richmond, USA: Virginia Department of Conservation and Recreation, Division of Natural Heritage. https://www.dcr.virginia.gov/natural-heritage/document/nh-invasive-plant-list-2014.pdf

Hwang KiSeon, Eom MinYong, Park SuHyuk, Won OkJae, Lee InYong, Park KeeWoong, 2015. Occurrence and distribution of weed species on horticulture fields in Chungnam province of Korea. Journal of Ecology and Environment. 38 (3), 353-360. DOI:10.5141/ecoenv.2015.036

Liu Z H, Cong Y L, Lu B H, Gao J, 2016. First report of milkvetch (Astragalus propinquus) as a natural host of dodder (Cuscuta australis) in China. Plant Disease. 100 (2), 538. http://apsjournals.apsnet.org/loi/pdis

Missouri Botanical Garden, 2019. Tropicos database. In: Tropicos database. St. Louis, Missouri, USA: Missouri Botanical Garden. http://www.tropicos.org/

Panke B, Renz M, 2013. Management of invasive plants in Wisconsin: Japanese hop (Humulus japonicus) (A3924-26)., Madison, USA: Cooperative Extension, University of Wisconsin-Extension. 4 pp. https://cdn.shopify.com/s/files/1/0145/8808/4272/files/A3924-26.pdf

Rao Q, Luo C, Zhang H, Guo X, Devine G J, 2011. Distribution and dynamics of Bemisia tabaci invasive biotypes in central China. Bulletin of Entomological Research. 101 (1), 81-88. DOI:10.1017/S0007485310000428

Swearingen J, Bargeron C, 2020. Invasive Plant Atlas of the United States. In: Invasive Plant Atlas of the United States, Tifton, Georgia, USA: University of Georgia Center for Invasive Species and Ecosystem Health. http://www.invasiveplantatlas.org/

Swearingen J, Slattery B, Reshetiloff K, Zwicker S, 2010. Plant invaders of mid-Atlantic natural areas. Washington DC, USA: National Park Service and US Fish and Wildlife Service. 168 pp. https://www.invasive.org/alien/pubs/midatlantic/midatlantic.pdf

Tennessee Invasive Plant Council, 2017. Tennesse Invasive Plant Council 2017 List. Knoxville, USA: Tennessee Invasive Plant Council. https://www.tnipc.org/revised-list-of-invasive-plants/

USDA-NRCS, 2019. The PLANTS Database. In: The PLANTS Database. Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov

Wang R, Wang N, Ye T, Chen S Y, Fan Z F, Zhou T, 2013. Occurrence of Beet western yellows virus in Japanese hop (Humulus scandens) in China. Journal of Plant Pathology. 95 (2), 450. http://sipav.org/main/jpp/index.php/jpp/article/view/2843

West Virginia Division of Natural Resources, 2009. Invasive plant species of West Virginia., Elkins, USA: West Virginia Division of Natural Resources. 6 pp. http://www.wvdnr.gov/wildlife/Handout%20Invasive%20Plants%20of%20WV%202009.pdf

Yoon J Y, Choi G S, Jang S W, Park S H, Choi S K, 2018. First report of Tomato spotted wilt virus in Humulus japonicus in Korea. Plant Disease. 102 (3), 690-691. DOI:10.1094/pdis-07-17-1091-pdn

Links to Websites

Top of page
WebsiteURLComment
Global register of Introduced and Invasive species (GRIIS)http://griis.org/Data source for updated system data added to species habitat list.

Principal Source

Top of page

Draft datasheet under review

Contributors

Top of page

03/01/20 Original text by:

Nick Pasiecznik, Consultant, France

Distribution Maps

Top of page
You can pan and zoom the map
Save map
Select a dataset
Map Legends
  • CABI Summary Records
Map Filters
Extent
Invasive
Origin
Third party data sources: