Iowa State University

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Iowa's Noxious Weeds
Bob Hartzler

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The intent of the noxious weed law is to protect landowners from having their land invaded by weeds growing on adjacent land.  A copy of the Iowa Weed Law is found on this website.  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 control the weeds and charge the landowner for the costs of the control tactic.  The noxious weeds are classed either 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.

Current noxious weeds are listed below.  Images of each weed can be observed by clicking on the appropriate name.  The majority of linked pages were developed for Agronomy 217, Weed Identification.

Primary noxious weeds 1                                        Secondary noxious weeds1

quackgrass (Agropyron repens)                                         velvetleaf (Abutilon theophrasti)

perennial sowthistle(Sonchus arvensis)                             cocklebur (Xanthium commune)

Canada thistle(Cirsium arvense)2                                      wild mustard (Brassica arvensis)

bull thistle (Cirsium lanceolatum)2                                      wild carrot (Daucus carota)

field bindweed (Convolvulus arvensis)                                  sheep sorrel, red sorrel (Rumex acetosella)

horsenettle (Solanum carolinense),                                     sour dock , curly dock (Rumex crispus)

leafy spurge (Euphorbia esula)                                           smooth dock (Rumex altissimus)

perennial pepper-grass, hoary cress (Lepidium draba)          poison hemlock (Conium maculatum)

Russian knapweed (Centaurea repens)                                multiflora rose (Rosa multiflora)

buckthorn (not to include Rhamnus frangula)                        wild sunflower (Helianthus annus L.)

musk thistle (Carduus nutans)2                                           puncturevine (Tribulus terrestris)

tall thistle (Cirsium altissimum)2                                          teasel(Dipsacus spp.)

                                                                                        shattercane (Sorghum bicolor)

                                                                                        buckhorn plantain (Plantago lanceolata)


1The botanical names listed on this page are reproduced as found in the Iowa Weed Law.  Several names have been changed (e.g. quackgrass, cocklebur) since the Weed Law was last revised.

2The Iowa Weed Law states that all thistles in the Carduus and Cirsium genus are considered noxious, so several other thistles of lesser importance are included in the law.

Prepared by Bob Hartzler, extension weed management specialist, Department of Agronomy, Iowa State University

For more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
Submit questions or comments here.  

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Common chemical and trade names are used in this publication. The use of trade names is for clarity by the reader. Inclusion of a trade name does not imply endorsement of that particular brand of herbicide and exclusion does not imply nonapproval.