This month, since weeds are currently dormant, instead of focusing on a specific weed, we’ll introduce you to a valuable resource from the Minnesota Department of Agriculture (MDA) called the Minnesota Noxious Weed List. While there are some ‘good’ weeds, there also are weeds that are more than just a nuisance to the gardener. They actually represent a threat to human or animal health, our eco-systems, crops, livestock, and other property. We all have a role in knowing more about these weeds and the steps to manage or eradicate them. This Noxious Weed website also contains information on how to report noxious weeds to the county, state, or federal agencies responsible for management. Minnesota State Statute,  M.S. 18.771 directs the commissioner of MDA to classify these noxious weeds into one of five categories. 

An overview of the categories is provided below along with a couple of examples of the weeds in that category. We encourage you to visit the link to the noxious weed list provided above to review the tables of noxious weeds and learn more about the specific plants. You may be surprised to see some familiar trees, shrubs, and flowers listed as weeds! Each plant designated as a noxious weed has its own page that includes: 

• Pictures 

• Scientific and common names

• Legal status

• Background

• Description

• Habitat

• Means of spread and distribution

• Impact

• Prevention and management

• Toxicity

The five categories of noxious weed are: 

1. Prohibited Eradicate Noxious Weeds

2. Prohibited Control Noxious Weeds

3. Restricted Noxious Weeds

4. Specially Regulated Plants 

5. County Noxious Weeds 

An additional category exists called Federal Noxious Weeds. The MDA website notes that “federal terrestrial and parasitic listed noxious weeds are prohibited in Minnesota”. These weeds are under the auspices of the U.S. Department of Agriculture (USDA) and they select and enforce them. You can learn more about the federal weed program at the USDA APHIS website.

1. Prohibited Eradicate Noxious Weeds

This weed category includes weeds that must be eradicated across the whole state. These weeds are prohibited from being transported and may not be sold or propagated in Minnesota. Examples of Prohibited Eradicate Noxious Weeds include: Black swallow-wort, Grecian foxglove, and Tree of heaven.

2. Prohibited Control Noxious Weeds

The weeds in this category must be controlled anywhere they may be found in Minnesota. Like the previous category, these weeds cannot be transported, propagated, or sold. Examples include Canada Thistle, Leafy Spurge, Purple Loosestrife, and Wild Parsnip. 

3. Restricted Noxious Weeds

Restricted noxious weeds and their propagating parts are only allowed to be imported, sold, or transported if allowed by permit under section 18.82. Examples include: crown vetch, Japanese Barberry, Garlic Mustard, and Wild Carrot/Queen Anne’s Lace. 

4. Specially Regulated Plants

These weeds may be native or nonnative species that have some economic value but may also cause harm in noncontrolled environments. Ecological or economical harm may occur and there are human or animal health concerns. Examples include: Amur Maple, Norway Maple (and all cultivars), and Poison Ivy. 

5. County Noxious Weeds 

Individual county boards may designate plants as noxious weeds and prohibit them within the county’s jurisdiction. However, these designations must be approved by the Commissioner of Agriculture, who consults with the Noxious Weed Advisory Committee. 

If you are interested in learning more about noxious weeds in Minnesota, you can subscribe to the Noxious Weed of the Month article. Every month, you’ll get an email from the Minnesota Department of Agriculture with information on a noxious weed. To subscribe, Click here to sign up for Weed of the Month emails.

We are bringing you a new series this year, “Weed of the Month”. Some months, we’ll highlight a specific weed, show you what it looks like, describe its key characteristics, and methods for managing it. Other months we’ll focus on a special angle about weeds, for example, edible weeds because it turns out that not all weeds are bad! This article provides a very useful set of resources to identify and understand weeds and how you should handle them.

Photo credits: Minnesota Department of Agriculture (1,4), University of Minnesota Extension (2), University of Minnesota Extension, Dana Boyle (3)