Japanese hop
Humulus japonicus Siebold & Zucc.
Description from Invasive.org
- Appearance
- Humulus japonicus 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.
- Foliage
- Leaves are opposite, rough, 2-5 in. (5-13 cm) long, 5-9 lobed with toothed margins. Most leaves will have five lobes, but the upper leaves may only have three.
- Flowers
- Flowers originate in the leaf axils and are green with five 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
- Fruit is a yellow-brown ovoid achene. The small seeds are distributed by wind and water.
- Ecological Threat
- These vines can grow to 35 ft. (10.7 m) in one growing season, allowing them to infest large areas crowding and out competing native vegetation. Humulus japonicus was introduced into North America in the mid-to-late 1800s as an ornamental.
Resources
- Weed of the Week - USDA Forest Service
- Weeds Gone Wild Fact Sheet - Plant Conservation Alliance, Alien Plant Working Group
- Plant Invaders of Mid-Atlantic Natural Areas - National Park Service
Selected Images from Invasive.org
View All Images at Invasive.org
Flower(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Feature(s) The down-curved bracts and sharp prickles help to identify this plant
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage
Foliage Leaves and Inflorescences
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Fruit(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Flower(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Foliage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Infestation
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Plant(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage
