Extension Logo
Extension Logo
University of Minnesota Extension
https://extension.umn.edu

Japanese hops

Quick facts

Japanese hops are an invasive species.

  • Japanese hops are found in sunny riparian areas, grasslands, hayfields and roadsides.
  • This vine aggressively climbs over trees and larger vegetation, creating dense patches and choking out other vegetation.
  • The tiny hairs on the stem can irritate bare skin.

Japanese hops should be reported. The Minnesota Department of Natural Resources provides detailed recommendations for reporting invasive species.

large bush of Japanese hops

How to identify Japanese hops

  • Annual vine with palmately arranged leaves.
  • Can grow up to 35 feet in a single growing season.
  • Stems and leaves have hooked hairs.

Stem

  • Stems are covered with downward-pointing prickles.

Leaves

  • Opposite, toothed leaves are divided into five to seven lobes; two to five inches long.

  • Bracts occur where the leaf petioles attach to the stem.

Flowers

  • There are separate male and female plants.
  • Flowers occur in clusters, are green in color and don’t have petals.
  • Male flowers are upright while female flower clusters droop down.
  • Blooms mid to late summer.

Fruit

  • Single flattened seeds from each female flower.
  • Each inflorescence produces several seeds that mature in September.

Seeds

  • Plant produces yellow-brown achenes.
  • Seeds remain viable in soil for up to three years.
  • Whole hops can float and travel in the current for dispersal.

Roots

  • Younger plants have small white roots that quickly establish into a fibrous mass.
  • Roots easily break off when pulled and quickly resprout another vine.
Japanese hops stem
Japanese hops
downward facing pointy Japanese hops flowers
Japanese hops
Japanese hops plant with seven pointed leaves
Japanese hops

 

 

Angela Gupta, Extension educator; Amy Rager, Extension educator; Megan M. Weber, Extension educator

Reviewed in 2019

Share this page:

© 2019 Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer.