hooked hair hops: Humulus japonicus (Urticales: Cannabaceae): Invasive Plant Atlas of the United States

hooked hair hops	USDA PLANTS Symbol: HUJA U.S. Nativity: Exotic Habit: Vines
Humulus japonicus Siebold & Zucc.

Jump to: Resources | Images | Distribution Maps | Sources

Taxonomic Rank: Magnoliopsida: Urticales: Cannabaceae
Native Range: Temp. Asia - China, Japan, & Russ. Fed (GRIN);
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.

Identification, Biology, Control and Management 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

Infestation; Chris Evans, University of Illinois, Bugwood.org Additional Resolutions & Image Usage	Foliage; Chris Evans, University of Illinois, Bugwood.org Additional Resolutions & Image Usage	Foliage; Chris Evans, University of Illinois, Bugwood.org Additional Resolutions & Image Usage	Flower(s); 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	Foliage; Leaves and Inflorescences 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	Flower(s); 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	Infestation; 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	Seed(s); Carole Ritchie, USDA NRCS PLANTS Database, Bugwood.org Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org