Humulus scandens (Japanese hop)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Plant Type
- Distribution
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat
- Habitat List
- Biology and Ecology
- Climate
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Impact
- Risk and Impact Factors
- Uses
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Links to Websites
- Principal Source
- Contributors
- Distribution Maps
Don't need the entire report?
Generate a print friendly version containing only the sections you need.
Generate reportIdentity
Top of pagePreferred 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 pageHumulus 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 pageHumulus 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 pageThe 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.
Distribution
Top of pageHumulus 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 pageThe 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: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Asia |
|||||||
China | Present | Native | |||||
-Anhui | Present | Native | |||||
-Beijing | Present | ||||||
-Fujian | Present | Native | |||||
-Guangdong | Present | Native | |||||
-Guangxi | Present | Native | |||||
-Guizhou | Present | Native | |||||
-Hainan | Present | Native | |||||
-Hebei | Present | Native | |||||
-Heilongjiang | Present | Native | |||||
-Henan | Present | Native | |||||
-Hubei | Present | Native | |||||
-Hunan | Present | Native | |||||
-Jiangsu | Present | Native | |||||
-Jiangxi | Present | Native | |||||
-Jilin | Present | Native | |||||
-Liaoning | Present | Native | |||||
-Shaanxi | Present | Native | |||||
-Shandong | Present | Native | |||||
-Shanxi | Present | Native | |||||
-Sichuan | Present | Native | |||||
-Tibet | Present | ||||||
-Yunnan | Present | Native | |||||
-Zhejiang | Present | Native | |||||
Japan | Present | Native | |||||
-Hokkaido | Present | Native | |||||
-Honshu | Present | Native | |||||
-Kyushu | Present | Native | |||||
-Ryukyu Islands | Present | Native | |||||
-Shikoku | Present | Native | |||||
Mongolia | Present | Native | |||||
North Korea | Present | Native | |||||
South Korea | Present | Native | |||||
Taiwan | Present | ||||||
Vietnam | Present | Native | |||||
Europe |
|||||||
Belgium | Present | Introduced | Listed as a casual alien | ||||
Czechia | Present | ||||||
France | Present | Introduced | Invasive | ||||
Germany | Present | Introduced | |||||
Hungary | Present | Introduced | Invasive | ||||
Italy | Present | Introduced | Invasive | ||||
Poland | Present | Introduced | 1928 | ||||
Romania | Present | Introduced | 1942 | ||||
Russia | Present | Native | |||||
-Russian Far East | Present | Native | |||||
Serbia | Present | Introduced | |||||
Slovakia | Present | Introduced | 1933 | ||||
Slovenia | Present | Introduced | |||||
Switzerland | Present | Introduced | |||||
Ukraine | Present | Introduced | |||||
North America |
|||||||
Canada | Present | Introduced | 1903 | As: Humulus japonicus | |||
-Ontario | Present | Introduced | |||||
-Quebec | Present | Introduced | |||||
United States | Present | Introduced | Invasive | ||||
-Alabama | Present | Introduced | |||||
-Arkansas | Present | Introduced | |||||
-Connecticut | Present | Introduced | Invasive | ||||
-Delaware | Present | Introduced | Invasive | ||||
-District of Columbia | Present | Introduced | Invasive | ||||
-Georgia | Present | Introduced | |||||
-Illinois | Present | Introduced | |||||
-Indiana | Present | Introduced | Invasive | ||||
-Iowa | Present | Introduced | |||||
-Kentucky | Present | Introduced | |||||
-Maine | Present | Introduced | |||||
-Maryland | Present | Introduced | Invasive | ||||
-Massachusetts | Present | Introduced | |||||
-Michigan | Present | Introduced | |||||
-Minnesota | Present | Introduced | |||||
-Missouri | Present | Introduced | |||||
-Nebraska | Present | Introduced | |||||
-New Hampshire | Present | Introduced | |||||
-New Jersey | Present | Introduced | |||||
-New York | Present | Introduced | |||||
-North Carolina | Present | Introduced | |||||
-North Dakota | Present | Introduced | |||||
-Ohio | Present | Introduced | |||||
-Pennsylvania | Present | Introduced | Invasive | ||||
-Rhode Island | Present | Introduced | |||||
-South Carolina | Present | Introduced | |||||
-South Dakota | Present | Introduced | |||||
-Tennessee | Present | Introduced | Invasive | Listed as an emerging threat | |||
-Vermont | Present | Introduced | |||||
-Virginia | Present | Introduced | Invasive | Ranked as exhibiting medium level of invasiveness based on its threat to natural communities and native species | |||
-West Virginia | Present | Introduced | Invasive | Designated as occasionally invasive generally not affecting ecosystem processes but may alter plant community composition by outcompeting one or more native plant species | |||
-Wisconsin | Present | Introduced | Invasive |
History of Introduction and Spread
Top of pageHumulus 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., 2004; Balogh 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, 1909; Arrigoni 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 pageHumulus 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 pageIn 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 pageCategory | Sub-Category | Habitat | Presence | Status |
---|---|---|---|---|
Terrestrial | Managed | Disturbed areas | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Managed | Rail / roadsides | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Managed | Rail / roadsides | Present, no further details | Natural |
Terrestrial | Natural / Semi-natural | Natural forests | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Natural forests | Present, no further details | Natural |
Terrestrial | Natural / Semi-natural | Natural grasslands | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Natural grasslands | Present, no further details | Natural |
Terrestrial | Natural / Semi-natural | Riverbanks | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Riverbanks | Present, no further details | Natural |
Terrestrial | Natural / Semi-natural | Wetlands | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Wetlands | Present, no further details | Natural |
Biology and Ecology
Top of pageGenetics
The chromosome number of H. scandens is 2n = 16 = 14 + XX in female plants and 2n = 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 pageClimate | Status | Description | Remark |
---|---|---|---|
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 pageNatural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
---|---|---|---|---|---|---|
Cladosporium | Pathogen | |||||
Fusarium | Pathogen | |||||
Oidium | Pathogen |
Notes on Natural Enemies
Top of pageZheng 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 pageHumulus 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 Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Disturbance | Yes | |||
Escape from confinement or garden escape | Yes | |||
Flooding and other natural disasters | Yes | |||
Garden waste disposal | Yes | |||
Horticulture | Yes | Yes | ||
Internet sales | Yes | |||
Landscape improvement | Yes | Yes | ||
Nursery trade | Yes | Yes | ||
Ornamental purposes | Yes | Yes | ||
Seed trade | Yes | Yes |
Impact Summary
Top of pageCategory | Impact |
---|---|
Cultural/amenity | Negative |
Economic/livelihood | Negative |
Environment (generally) | Negative |
Human health | Negative |
Impact
Top of pageIn 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- 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
- 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
- Causes allergic responses
- Competition - monopolizing resources
- Competition - smothering
- Rapid growth
- Highly likely to be transported internationally deliberately
- Difficult to identify/detect as a commodity contaminant
Uses
Top of pageIn 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).
Similarities to Other Species/Conditions
Top of pageHumulus 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 pageDue 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 pageAlexandrov 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.
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.
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.
Fried G, 2017. Guide des plantes invasives, Paris, France: Belin.302 pp.
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.
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.
Meyers-Rice B, 2014. Weed notes: Humulus japonicus. USA: https://wiki.bugwood.org/Humulus_japonicus
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
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.
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.
Distribution References
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
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
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
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/
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
Links to Websites
Top of pageWebsite | URL | Comment |
---|---|---|
Global register of Introduced and Invasive species (GRIIS) | http://griis.org/ | Data source for updated system data added to species habitat list. |
Distribution Maps
Top of pageSelect a dataset
Map Legends
-
CABI Summary Records
Map Filters
Unsupported Web Browser:
One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/