Invasive Species in Iowa

Invasive species are a significant challenge affecting the health of Iowa's natural communities. Most invasive species are exotic but some native species can become invasive as well. When species become invasive they often reduce biodiversity by out-competing native species, which can disrupt entire ecosystems. Invasive species are introduced in various ways. They can arrive in new areas accidentally through human trade and travel, sometimes they are intentionally introduced for ornamental or ecological reasons, or they can naturally expand their ranges into new areas when the climate changes and no longer limits their growth. When a species is introduced into an area where it is not naturally found it becomes invasive if there are no controls such as predators, herbivores, resource competitors, diseases, or climatic inhibitors to prevent it from continuing to spread. Species that become invasive also often reproduce rapidly or have life cycle differences that give them an advantage over native species. Invasive species are often generalists that do not have strict habitat requirements, and can therefore have few limiting conditions that prevent them from thriving.

Iowa's forests, prairies, and aquatic environments all face unique invasive species threats. Certain invasive species affect specific species of plants and animals as well. In Iowa, invasive species come in all shapes and sizes, ranging from microscopic fungal pathogens affecting bats or trees to ubiquitous, easily recognizable species like feral cats or multiflora rose.

Luckily many invasive species can be identified and controlled and native communities can be restored.

Exotic Invasive Plants

common buckthorn flowers on a plant
Photo by Rob Routledge, Sault College, Bugwood.org

Buckthorn

Buckthorn can be a large shrub or small tree. Common buckthorn is listed as a primary noxious weed in Iowa and both species in the state serve as hosts for soybean aphids. Check out this page to learn more about buckthorn and find out how to control infestations. 

exotic burning bush with red foliage
Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Burning Bush

Exotic burning bush is a common and popular plant used in landscaping. Unfortunately it can escape from yards and invade forests where it shades and crowds out native vegetation. Check out this page to find out about the native burning bush species and how to control the exotic one. 

garlic mustard plant in bloom
Photo by Richard Gardner, Bugwood.org

Garlic Mustard

Garlic mustard is a highly invasive biennial forb that has quickly invaded many of Iowa's forests. Check out this page to learn more about what garlic mustard looks like how to control garlic mustard infestations. 

honeysuckle plant in bloom with white flowers
Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Honeysuckle

Unlike native honeysuckle spices, exotic honeysuckles form dense thickets that prevent native plants from growing and reduce the quality of forest habitat. Check out this page to learn more about honeysuckles and how to control infestations.      

Japanese barberry plant with red foliage

Japanese Barberry

Japanese barberry is a popular landscaping plant because of its uniquely colored leaves. However, it is best not to plant this shrub because it can spread to nearby native forest habitat and become invasive. Check out this page to learn more about Japanese barberry and how to control infestations.    

multiflora rose plant in bloom with white flowers
Photo by James H Miller, USDA Forest Service, Bugwood.org

Multiflora Rose

Unlike Iowa's native wild prairie rose, the exotic multiflora rose forms dense thickets that can quickly reduce the growth of native vegetation. Check out this page to learn more about multiflora rose and how to control infestations.     

oriental bittersweet red and orange berries
Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Oriental Bittersweet

Oriental bittersweet is a woody vine that is popular for wreath making and other crafting activities due to its vibrantly colored fruit. American bittersweet is the native species, which has similarly attractive fruit but doesn't grow into dense stands that kill trees and other native vegetation. Check out this page to find out more about differentiating between the two species and how to control Oriental bittersweet infestations.   

field of reed canary grass
Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Reed Canary Grass

Reed canary grass is a tall, fast growing grass that commonly invades wetlands. Infestations can become so dense that they are even capable of suppressing tree growth in floodplain forests. Check out this page to learn more about how to identify reed canary grass and what methods can be used to control it.  

  

Additional Resources

For additional information on invasive plants check out the Iowa DNR Invasive Plants page and the Midwest Invasive Plants Network Plant List. We also have an invasive species video series on YouTube