Seondary Roads Banner


Noxious & Invasive Weeds Of Johnson County

County Weed Commissioner
4810 Melrose Avenue West
Iowa City, IA 52246
PH: (319) 356-6046


Report Weed Infestation Button

Noxious Weeds Policy
Roadside Maintenance Agreement
Noxious Weeds - Why Should We Worry?
What Exactly is a Noxious Weed?
Why Should I Control Noxious Weeds?
Noxious Weed Species
Invasive Weed Species
What Can You Do To Help?
Who Controls Noxious Weeds in Johnson County?
How Do I Contact The County Weed Commissioner?
Code of Iowa, Chapter 317 Weeds
Noxious Weeds Resolution
Integrated Roadside Vegetation Management Plan
Related Websites

BulletNoxious Weeds - Why Should We Worry?

Should we worry whether the plants growing around us are native to our area or not? Isn’t it all just "nature?" Before you dismiss this issue as unimportant, consider the following:

• Noxious and invasive weeds in agricultural and natural areas cost our country $13 Billion dollars per year

• Noxious and invasive weeds are the second most important reason for the loss of biological diversity, after habitat destruction

• The Bureau of Land Management, our nation’s largest public landowner, estimates that 2,300 acres per day of its land are being lost to noxious and invasive plants. Nearly 4,000 acres per day are estimated to be lost to weeds nationwide.

If you find yourself alarmed by these facts, you are not alone. Local and state agencies, groups, and individuals have been quietly pouring money and resources for years into our local roadsides, parks, natural areas, and agricultural areas to combat this pressing problem. This web site is dedicated to raising public awareness of this issue. The battle against noxious and invasive weeds cannot be won without public awareness and support. As a homeowner, landowner, or land manager, your actions have a direct effect on this problem, because many weeds escape from yards and gardens.

This web site has, in addition, been prepared to help you understand the problems of noxious and invasive weeds, identify them around your home and community, and take direct action to save our natural and agricultural resources from this threat.

BulletWhat Exactly is a Noxious Weed?

Many people are familiar with the concept of weeds in the context of their yard or garden. Weeds are simply undesirable plant species. The same principle holds true for Johnson County’s roadsides, natural areas, farm fields, etc., which are home to a diverse array of native plants. The number and variety of these native species is described by the term "biological diversity." Over the past 150 years, many non-native plants have been introduced to our region, both intentionally and accidentally. The vast majority of these plants coexist with native species, and are ecologically harmless.

What makes a plant noxious in the context of Johnson County’s natural resources, is its negative impact on agriculture, or its ability to spread and crowd out native plants. This is why noxious weeds are distinguished from those weeds that occur in small numbers and are innocuous. Noxious weeds are those able to reproduce in the wild, spread rapidly, which are difficult to control, or which cause the decline or loss of our native plants. It is not completely understood why some weeds become noxious and some don’t. But because noxious weeds did not evolve locally, their populations are not held in check by natural predators or diseases, giving them a competitive edge over native plants. Noxious weed species can proliferate and spread over large areas. Some are able to completely displace other vegetation, forming a homogenous (single species) cover. Contrast this situation with the rich variety and diversity of a native plant community such as is seen in prairies, wetlands, or forests.

Noxious weeds are exotic plants that have reached Johnson County and Iowa by escaping from gardens, being transported by hay or straw, air, dirt, tires, clothing, etc. They grow aggressively, lack natural enemies, and resist management methods. These species can move quickly into bare areas which have been disturbed by construction or erosion, have poor vegetative cover, or have other soil disturbances. Some of Iowa’s noxious weeds are spread by wind blown seed, birds, or other organisms. Other weeds spread though poorly timed mowing, or baling of hay to be fed to livestock or sold. And other noxious weeds spread by sending rhizomes (long underground roots) to uninfested areas. Most of Iowa’s noxious weeds can be easily controlled through proper management. Use of mowing, cutting, burning, competitive seeding, cultivation, herbicide usage, etc., are some of the various techniques used to combat weeds. Several of the State of Iowa and Johnson County’s worst noxious weeds are very difficult to control, such as Canada Thistle, Japanese Knotweed, or Purple Loosestrife. A primary key to weed control is early detection and management, before that weed has spread and built up a large seed bank and energy reserve.

BulletWhy Should I Control Noxious Weeds?

Noxious Weeds and other invasive species threaten all of our natural resources. They can destroy native plant and animal habitat, damage recreational areas, clog waterways, lower land values, decrease agricultural crop yields, and some can even poison humans and livestock. Noxious Weeds are also a leading cause of species endangerment under the Endangered Species Act. The Iowa Dept. of Agriculture & Land Stewardship, along with Johnson County, has declared 31 species of plants as Noxious. A complete list of plants considered noxious by Johnson County or the State of Iowa is included with this web site.

BulletWho Controls Noxious Weeds in Johnson County?

All landowners are required to control noxious weeds on their property to eliminate seed production. Weeds growing within city limits, in abandoned cemeteries, along railroads, streets, and highways, as well as on farmland, or any private or public land, must be controlled. The Johnson County Weed Commissioner enforces the Iowa Noxious Weed Law (Chapter 317). To learn more about Iowa’s Weed Law, click here .

BulletHow Do I Contact The County Weed Commissioner?

Every county in Iowa has a weed commissioner to oversee that County’s noxious weed control program. The Johnson County Weed Commissioner is located at the Secondary Road Dept., 4810 Melrose Ave, Iowa City, IA 52246. Phone (319) 356-6046.

BulletWhat Can You Do To Help?

Don’t Plant Invasive Weeds. Be selective when you choose plants for home landscaping. Some invasive plants, such as purple loosestrife varieties, are still sold in nurseries and garden shops, so beware! If you plant these in your yard, they may escape into nearby natural areas and become a problem by displacing native species. Not all non-native plants are invasive. There are many beautiful horticultural plants available for you to choose from, without contributing to the noxious or invasive weed problem. Also consider planting native species in your home garden. Natives offer a good choice for home landscaping because they are well adapted to local conditions and often thrive with less care than required by many non-native plants. Native plant gardening also enhances the value of your yard for local wildlife including birds and butterflies.

Remove Invasive Weeds. Be on the lookout for noxious or invasive weeds and remove or report them whenever possible. You may have invasive plants already growing in your backyard. Birds and other animals may eat the seeds of these plants and then travel to nearby uninfested lands, resulting in the spread of noxious weeds. You can help stop these invasions by removing the source plants. Talk to your neighbors about the problem and share your concerns. Report sightings on public lands to the land manager. And if you do remove these plants from your own land, be sure not to spread the seeds when disposing of them.

Help Prevent the Accidental Spread of Noxious Weeds. When you venture into natural areas, roadsides, or any place with noxious weeds, be aware that you could be introducing or carrying invasive weeds inadvertently. Check your shoes, socks, clothing, etc., which might carry seeds. Another important thing you can do is to try to limit soil disturbances, if possible, on your property. Noxious weeds thrive on disturbance and can quickly colonize areas which don’t have a good vegetative cover. If noxious weeds are moving in, try to control them before they get well established and the area is infested.

Educate Yourself And Spread The Word. Become better informed about how to identify noxious and invasive weeds, how to avoid spreading them, and how to control them. The battle to control noxious weeds cannot be won without public awareness and support. Then share what you have learned so that others can join in the WAR ON WEEDS!

Here are some groups and agencies that can provide further information or assistance on noxious weeds:
• Johnson County Roadside Vegetation Manager/ Weed Commissioner (319) 356-6046
• Johnson County Extension Service (319) 337-2145
• Iowa Department of Agriculture & Land Stewardship (515) 281-5321
• Natural Resource Conservation Service (319) 337-2322
• Iowa Department of Transportation (515) 233-7729
• Iowa State University (Agronomy) (515) 294-1923
• The Nature Conservancy (515) 244-5044

BulletRelated Websites

• : The Nation's Invasive Species Information System
Bureau of Land Management Environmental Education Homepage
Bureau of Land Management Weeds Website
University of Northern Iowa Roadside Program
•  Iowa's Living Roadway Trustfund