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.
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 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 is a yellow-brown ovoid achene. The small seeds are distributed by wind and water.
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.
Japanese hops can form dense patches that outcompete and smother native vegetation.
This vine is native to China, Japan, Korea and Taiwan. It was brought to the U.S. in the mid-to-late 1800s as an ornamental and as a medicinal plant. This is not the type of hops used for beer making.
Meadows, fields, disturbed areas
Japanese hops is an annual, climbing or trailing vine that can grow up to 35 feet in length in one growing season. Female flowers appear in mid summer as cone-shaped clusters that hang down (called hops), while male flowers are upright and stemlike.