Species of Concern

Species Spotlight: Japanese Hops (Humulus japonicus)

Japanese hops is an annual vine that blankets other vegetation as seen in the picture.  It thrives along the banks of rivers in deposited sediment and spreads by seed during high flow events, as it did in during the floods of 2007 and 2008 within the Platte River watershed in Grant County, Wisconsin.  Seeds are believed to be viable for up to three years.  It prefers full to partial shade. Its leaves are plamately lobed, having typically 5 or more lobes.  The stems and undersides of the leaves are covered in rough hairs that it uses to climb other vegetation.  Its flowers are small and greenish.  The male and female flowers are found on seperate plants.

At this time Japanese hops is known to exist in only five counties in Wisconsin.  Please be on the lookout for this plant and report it immediately by calling (608) 267-7438.  It is important that we quickly identify and control all new shoreline populations to prevent further spread throughout the state.  

Japanese hops is just 1 of 12 species featured on the new publication available online created by the River Alliance and the WDNR:  River and Wetland Invasive Plants.


Species of Concern:

The species below have been identified as a threat to Wisconsin’s rivers.  Click on the links to various factsheets to learn more about each species.

Other References:

Wisconsin DNR Invasive Species Webpage
Wisconsin Invasive Species Distribution Maps
Midwest Invasive Plant Network (MIPN) Homepage
Minnesota Sea Grant Invasive Species Webpage
Project RED Data on CitSci.org
Trout Unlimited Aquatic Invasive Species Page