Invasive Species Awareness Week resources

updated 2-22-23
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The last week of February is Invasive Species Awareness Week, which is "an international event to raise awareness about invasive species, the threat that they pose, and what can be done to prevent their spread."

Iowa's landscape has many non-native plant and animals species that can wreak havoc on native plant & wildlife communities, as well as cause economic damage. Invasive species have varying levels of concern depending on their impacts. Some invasive species cause relatively few problems, while others can destroy native ecosystems. Some require action to avoid legal consequences, while others are more a concern to land managers working to restore prairies and savannas. 

Eastern red cedar (Juniperus virginiana), for example, is one species that can take over and shade out native prairie species, resulting in dense monocultures of coniferous trees where almost no other species can survive. Although they are actually native to the region, removing fire and grazing animals from the landscape has led to their proliferation in recent decades. ​

Example of a stand of dense cedars (left) and diverse remnant prairie (right) at Loess Hills State Forest.

Smooth brome (Bromus inermis) is a grass that was planted in livestock pastures, along roadsides, on terraces and grassed waterways,  and elsewhere across the Midwest. While it's not necessarily a problem in every site, it can be challenging to control in prairie restorations and reconstructions. If you have an area where you'd like to restore or create a prairie, you will need to manage the brome.

Crown vetch (Coronilla varia) is a non-native legume that was planted for erosion control and ground cover. It has physical similarities to native vetch species but should be eradicated. Reed canary grass (Phalaris arundinacea) prefers wetter areas and has resemblance to some native grasses. These species are problematic in prairies and wetlands because they can crowd out native species.

In woodlands, garlic mustard (Alliaria petiolata) is one of the most aggressive understory species. Like cedars, it can take over an area and prevent most other species from growing. Tree of heaven (Ailanthus altissima) was planted as an ornamental and is one of the fastest-growing and -reproducing woody species around. Garlic mustard and tree of heaven can quickly take over a woodland and prevent native species from growing. 

Some species are listed as noxious weeds and landowners have a legal obligation to remove them. If you have confirmed presence of noxious weeds on your land, you should take action to eradicate them. The links below have full listings of all invasive flora species in Iowa as well as fauna such as insects and aquatic species.

If you like the look of certain invasives, plant a native species with similar characteristics instead. Check out the Midwest Invasive Plant Network's Landscape Alternatives for Invasive Plants of the Midwest brochure and mobile app to help find native species. 

Golden Hills worked with Dr. Tom Rosburg of Drake University on a Common Weeds & Invasive Species virtual program in 2022. View the class recording here or below.

Here are several additional resources to learn more about invasive species in Iowa:

• Hawkeye Cooperative Weed Management Area - This website includes information and brochures about common invasive species in Iowa's grasslands and woodlands.
• Iowa Department of Natural Resources - Invasive plant species  - Information on invasive plant species in Iowa and how to identify and manage them. 
• ​USGS Nonindigenous Aquatic Species - List of invasive aquatic species in Iowa including plants, fish, mollusks, amphibians, & more. 
• ​Midwest Invasive Plant Network - Information about ivasive plants that are not native to the Midwest, and which cause (or are likely to cause) harm to environmental, economic, and/or human health. Information about native plant alternative to invasive species for home & garden. Resources for identifying and managing invasive species. 
• Iowa's Invasive Insect and Disease Watchlist -  maintained by the Entomology and Plant Science Bureau of the Iowa Department of Agriculture and Land Stewardship, these pages have info about invasive tree pests. 
• Iowa's Noxious Weed Law (Chapter 317) - "The intent of noxious weed laws is to protect landowners from having their land invaded by weeds growing on adjacent land, and to reduce the likelihood of introduction and spread of new weeds.  Iowa's noxious weed law is Chapter 317 of the Iowa Code.  The law gives each county the authority to order the destruction of weeds classified as noxious by the state.  If the owner of the land fails to address the weed problem, the county can assess the owner a fine, and if needed, control the weeds and charge the landowner for the costs of control.  Noxious weeds are classified as primary or secondary, but this status only applies to the Iowa Seed Law.  The Seed Law defines how many weed seeds can be present in certified crop seed.  Palmer amaranth was recently added to the list of primary noxious weeds, taking effect on July 1, 2017.  Counties have the authority to declare additional weeds as noxious within their borders."
• Impacts, Identification & Control of Invasive Species - Iowa State University Agriculture & Natural Resources Youtube series about impacts, identification, and control of Iowa invasive species. 
• Iowa Natural Heritage Foundation - 5 of Iowa's most invasive species (& how to get rid of them)