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New invasive weeds

Common tansy was recently identified along a roadside in northeast South Dakota. This weed has been well established in western Minnesota for several years, so it is not too surprising to see it in eastern South Dakota, says Mike Moechnig, South Dakota State University Extension weed specialist.

This common tansy is not yet widespread, but it has the potential to be invasive, so watching for this weed and controlling patches while they are small is critical, according to Moechnig.

Key Points

• Common tansy is a new weed to eastern South Dakota.

• Oxeye daisy is a problem in western South Dakota.

• Control these weeds while they are still in small patches.

Common tansy has already spread extensively in the Black Hills and is designated as a local noxious weed in Lawrence and Pennington counties.

Common tansy is a perennial that can spread by seed or roots. Livestock will generally avoid grazing it due to its bad taste, but there are some reports that it can be toxic if consumed in large quantities over an extended period of time.

Oxeye daisy

Oxeye daisy was added to the list of potential local noxious weeds in South Dakota this year. It will likely only be designated as a noxious weed in counties that include the Black Hills, Moechnig says.

Oxeye daisy also is established in eastern South Dakota, but it does not seem to be as invasive as in the west.

“It seems to persist around my house just north of Brookings but patches never become dense enough to suppress grass growth,” Moechnig says. “This plant produces large flowers so it is tempting to not control it, but it may be important to monitor populations and take action to prevent it from spreading to neighboring properties.”

For SDSU Extension recommendations of herbicides to control common tansy, oxeye daisy and other noxious weeds, go online to and click on “Noxious Weed Control in South Dakota” under Web Exclusives.

Source: South Dakota Pest Report

Houndstongue spreads in eastern South Dakota

Houndstongue is an invasive biennial or short-lived perennial weed. It is on the local noxious weed list in several counties.

Houndstongue is a very annoying weed that produces hundreds of sticky burs that can plaster your pant legs or tangle dog or livestock hair. It is currently spreading throughout the Black Hills area and is becoming a greater concern there. Populations are still small in eastern South Dakota. However, they may be expanding.

“I recently received a Houndstongue sample from the Arlington area,” says Mike Moechnig, South Dakota State University Extension weed specialist. “I have also heard reports of it growing in the Watertown area, and we know there are some infestations in Hand County. I encourage people to be looking for this weed and leave no survivors.”


Common tansy


Oxeye daisy

This article published in the September, 2012 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.