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Japanese hop (Humulus japonicus)

Posted in Species Profiles

Picture of Japanese hop infestation.
Although an annual plant, Japanese hop infestations can be very large.

Description: Japanese Hops is a herbaceous usually annual vine. Leaves are heart-shaped, palmately 5-lobed.Green flowers bloom mid to late summer. Male and female flowers appear on separate plants.

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Habitat: Japanese Hops can grow in sand, loam, clay, and acidic to basic soils, though soils must be moist. Plants grow in open woodlands, fields, praries, and riparian corridors.

Invasive Traits: Japanese establishes near water, which it uses to help disperse its seeds. It will reproduce vegetatively, quickly forming a dense cover, outcompeting native vegetation.

Picture of the prickly stalk of Japanese hop.
Downward-pointing prickles on Japanese hop stems allow it to climb over other plants, smothering them.

Control: Mechanical forms of control and removal are not recommended due to vigorous resprouting. Applying herbicide to leaves when rootstock is accumulating energy is most effective.

Further Reading

Pannil et al. 2009

Photo credits
  1. Cleveland Metroparks
  2. Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
  3. Chris Evans, Illinois Wildlife Action Plan, Bugwood.org