Report a weed infestation

Noxious Weed Species
Invasive Weed Species                                                
Integrated Roadside Vegetation Management Plan
Noxious Weeds Policy 
Roadside Maintenance Agreement

Noxious 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 website 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.

What 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.

Who 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).

Why 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 website.

What 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

How 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.

Code of Iowa, Chapter 317

DISCLAIMER -- This site contains provisions of the Iowa Constitution, the Code of Iowa, and the Iowa Acts. Although every attempt is made to ensure that the information placed on this site is accurate and timely, the Legislative Service Bureau and the Iowa General Assembly cannot assure the accuracy of any specific provision originating from this site, and you are urged to consult the official printed versions of these publications or to contact legal counsel of your choice. This site cannot legally be cited as an official or authoritative source.

The Code of Iowa Chapter 317 Weeds can be found here

Noxious Weeds Resolution

Resolution 04-06-00-01

Stigmatizing Noxious Weeds

Be it resolved: Pursuant to Chapter 317 of the Code of Iowa (1997) and upon recommendation of the Johnson County Weed Commissioner that the following weeds be declared noxious: Buckhorn Plantain, Buckthorn, Bull Thistle, Canada Thistle, Cocklebur, Field Bindweed, Hoary Cress, Horse Nettle, Japanese Knotweed, Leafy Spurge, Marijuana, Multiflora Rose, Musk Thistle, Perennial Peppergrass, Perennial Sow Thistle, Poison Hemlock, Poison Ivy, Puncturevine, Purple Loosestrife, Quackgrass, Red Sorrel, Russian Knapweed, Shattercane, Smooth Dock, Sour Dock, Tall Thistle, Teasel, Wild Parsnip, Wild Mustard and any other species listed as noxious under the Code of Iowa or deemed by the Weed Commissioner to present a major economic or environmental problem to Johnson County.

Be it further resolved that the Johnson County Board of Supervisors may order all noxious weeds within the right-of-way of all County trunk and local County roads to be cut, burned or otherwise controlled to prevent seed production either upon its own motion or upon receipt of written notice requesting said action from any residents of the township in which the affected roads are located, or any person regularly using these roads. The order and action shall be consistent with the Johnson County Integrated Roadside Vegetation Management Plan and in accord with the provisions of Section 317.18 of the Code of Iowa.

Be it further resolved that all noxious weeds shall be ordered to be destroyed by all landowners and tenants on or before the date of 1 June, 2000, so as to prevent the production of seed by all varieties of listed noxious weeds.

Be it further resolved that the Johnson County Weed Commissioner shall, upon failure of any landowner or tenant or both to comply with orders to destroy listed noxious weeds, be entitled to proceed to enter upon any lands within the County to destroy said noxious weeds upon notice as provided by Section 317.6 of the Code of Iowa, and to assess the actual costs thereof in accordance with Sections 317.6, 317.13 and 317.21 of the Code of Iowa. Actual costs of removal of weeds shall be estimated at not less than $50.00 per hour.

Be it further resolved that it is the policy of Johnson County that the Weed Commissioner shall direct control of all noxious weeds on public lands of Johnson County, Iowa, by cutting or mowing or by controlled burning or by the planting of competitive native vegetation as deemed necessary. Landowners, tenants or both may post “Do Not Spray” signs adjacent to their properties if deemed necessary and will be requested by the Weed Commissioner to respect areas of native vegetation planted to compete with noxious weeds if such treatment is applied adjacent to their properties. Designating signs shall be provided upon request and at no cost by the County and shall be observed in the event of any spraying operations or other treatment programs undertaken, providing that the landowner or tenant shall thereby assume responsibility for the destruction of all noxious weeds on those posted rights-of-way within Johnson County.

Be it further resolved that the Johnson County Weed Commissioner shall make every effort to provide treatment of all problem areas within the County without the use of chemical herbicides and to substitute appropriate methods of integrated vegetation management techniques wherever possible. A program of suitable alternative practices shall be developed and implemented to provide environmentally sound and long-term solutions to noxious weed problems within Johnson County under the direction of the Johnson County Roadside Vegetation Manager.

Be it further resolved that the Weed Commissioner shall act to encourage the good stewardship of land in Johnson County in order to further the control of noxious weeds which may cause any health or safety hazard to the residents of Johnson County. The control and eradication of noxious weeds has been deemed compatible with wise land management practices and wildlife protection policies. Noxious weeds shall not be substituted for appropriate ground covers, food supplies or protection for wildlife.

Related websites The Nation's Invasive Species Information System
Bureau of Land Management Education
Bureau of Land Management Weeds website
University of Northern Iowa Roadside Program
Iowa Administrative Code, Agriculture and Land Stewardship Department, Chapter 58 Noxious Weeds
Iowa's Living Roadway Trustfund