plants bloom in Wisconsin landscape
Invasive Species TNC works to prevent the spread of invasive species. © Steve S. Meyer

Stories in Wisconsin

Weeds at Their Worst: Combatting Invasive Species

Invasive species damage our lands and waters and make our lives miserable, but we can do something about them. Watch our video and learn more.

A bamboo-like plant strong enough to crack building foundations and pavement. A parsnip that makes your skin photo-sensitive when you brush against it and burns when exposed to sunlight. An aquatic plant that will ruin your day at the lake by getting caught in your boat propeller and making swimming nearly impossible.

Invasive, non-native species such as Japanese knotweed, wild parsnip and Eurasian water milfoil not only make people’s lives miserable, they cause serious damage to Wisconsin’s natural lands and waters. They out-compete native plants, replacing the food and cover that wildlife species depend on. The threat they pose is second only to the direct destruction of habitats through development.

All of Wisconsin’s native habitats—freshwater and terrestrial—are threatened by invasive species.

State agency spending in 2015 to manage Wisconsin’s invasive species exceeded $8.4 million according to a report to the Wisconsin Legislature; and that doesn’t include the cost to control invasive species on private lands including TNC preserves.

Invasive Species in Wisconsin They're doing a lot of damage to our natural world and costing a lot of money. But why are they so bad? Watch this video to learn how invasive species got here, why they’re such a nightmare for our native plants and animals, and what you can do to help stop their spread.


The Nature Conservancy works to prevent and control the spread of invasive species in Wisconsin, throughout the United States and in many countries around the world. Together with our partners we focus on:

  • Preventing future introductions & invasions of non-native invasive species
  • Quickly detecting and responding to new populations of invasive species when they occur
  • Protecting native habitats by minimizing the damage caused by invasive species that are challenging or impossible to eradicate

Land Management. The Nature Conservancy staff and volunteers actively control invasive species at our Wisconsin preserves through the careful application of controlled fire and herbicides, grazing, mowing and hand pulling.

Policy. TNC staff serve on the Wisconsin Invasive Species Council and provide scientific information about invasive species issues to State Agencies, legislators and other decision-makers.

Science. At our Lulu Lake Preserve in southeast Wisconsin, we are working with a University of Wisconsin-La Crosse scientist to test a new technique to help native aquatic plants compete with Eurasian water milfoil.

Partnerships. TNC joins state and federal agencies and a variety of private and non-profit groups to combat invasive species in Wisconsin.

  • In 2001, TNC joined a group of citizens concerned about invasive plants to help create the Invasive Plants Association of Wisconsin (IPAW). IPAW's mission is to promote better stewardship of Wisconsin’s natural resources by advancing the understanding of invasive plants and encouraging the control of their spread. We continue to be involved with IPAW, which provides resources for planning, preventing, controlling, monitoring and educating people about invasive plants.
  • TNC is also a member of the Midwest Invasive Plant Network, which was formed in 2002 to reduce the impact of invasive plant species across the Midwest. The network does this through information sharing and by creating tools for invasive plant prevention, early detection, education, control and management. One of those tools is an Invasive Plant Control Database, which contains information on how to control many invasive plants common to the Midwestern United States.
  • TNC is working with multiple partners to tackle Asian carp, zebra mussels and other aquatic invasive species in the Great Lakes.


Everyone can be part of the fight against invasive species. Consider removing invasive species in your yard or adding native plants or non-invasive horticultural plants. You can also volunteer for The Nature Conservancy, your local land trust or city park. Find upcoming TNC volunteer days and events.