Management of invasive knotweeds

photograph of Japanese knotweed in bloom with small white flowers

Japanese knotweed

Image credit: "Japanese knotweed" by Zachary Simek is licensed under CC BY-NC-ND 2.0


One of the largest vascular plants on earth is a single, female Japanese knotweed plant in the United Kingdom that has caused great environmental, economic, and property damage despite control efforts of around $2 billion a year. Genetic analysis helped researchers in the UK determine the single, clonal origin of their problem and how the plant was spreading asexually through the movement of stem and rhizome fragments.  

MITPPC researchers are looking to DNA for a better understanding of the invasive knotweed populations here in Minnesota. They will focus on Japanese knotweed (Polygonum cuspidatum) and giant knotweed (P. sachalinense), along with their hybrid Bohemian knotweed (P. x bohemicum).

By way of a new, low-cost genetic analysis commonly used in human disease research, Smith’s team will determine the genetic diversity of Minnesota knotweed populations and identify any genes linked to invasive traits or herbicide tolerance.

Research questions

  • What is the genetic diversity of knotweeds in Minnesota—what species and hybrids are in the population? 
  • Are Minnesota knotweeds spreading asexually, through stem and rhizome propagation, or sexually, through seed reproduction?
  • What markers for herbicide sensitivity and tolerance will a genome-wide study of invasive traits reveal?

Practical implications

This work will help experts understand Minnesota’s emerging invasive knotweed population and how control strategies should match the plant’s evolution. External partners will help produce a guide to best practice management recommendations for the region based on the project’s findings.


Research team

Alan Smith | principal investigator

Neil Anderson | co-principal investigator

Roger Becker | co-principal investigator

Matthew Clark | co-principal investigator

Marie Abbey | researcher

Youser Yousif | undergraduate

Grace Hart | undergraduate


Collaborating organizations

Minnesota Master Gardeners

University of Silesia in Poland

Minnesota Department of Agriculture

TechLine News

Oregon State University

US Department of Agriculture

Minnesota Department of Transportation

University of Canberra in Australia

Diversity Arrays Technology

Belgian Biodiversity Platform