Japanese hop

Urticales > Cannabaceae > Humulus japonicus Sieb. & Zucc

Japanese hop is an annual, climbing or trailing vine that is native to eastern Asia. This vine has 5-lobed leaves (generally), downward pointing prickles on the stem and bracts at the base of the petioles. Leaves are opposite, rough, 2-5 in. (5-13 cm) long, 5-9 lobed with toothed margins. Most leaves will have 5 lobes, but the upper leaves may only have 3. Flowers originate in the leaf axils and are green with 5 petals. Male and female flowers occur on separate plants (dioecious). Female flowers occur in cone-shaped clusters that hang down and the male flowers occur in upright flower stems. Fruit is an achene. Japanese hop was introduced into North America in the mid-to-late 1800s as an ornamental. These vines can grow to 35 ft. (10.7 m) in one growing season.


Identification, Biology, Control and Management Resources

  • Weeds of the Week - USDA Forest Service, Northeastern Area, Forest Health Protection

Selected Images from Invasive.org

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Foliage; Martin County, KY
Chris Evans, River to River CWMA, Bugwood.org
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Foliage; Martin County, KY
Chris Evans, River to River CWMA, Bugwood.org
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Feature(s); The down-curved bracts and sharp prickles help to identify this plant
Chris Evans, River to River CWMA, Bugwood.org
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Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Foliage; Leaves and Inflorescences
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Infestation; Martin County, KY
Chris Evans, River to River CWMA, Bugwood.org
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Plant(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Infestation;
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Seed(s);
Carole Ritchie, USDA NRCS PLANTS Database, Bugwood.org
768x512 / 1536x1024

Invasive Reference(s):

Check Invasive.org for most current lists.
  • Connecticut - Noxious Weed Law
  • Massachusetts - Noxious Weed Law
  • Virginia - Invasive Alien Plant Species
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
  • Invasive Plants of the Upper Midwest
  • Invasive Plant Atlas of New England


External Links


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USDA Forest Service Bugwood University of Georgia