What will kill this weed in our pastures? - Ask Extension
This weed has taken over one of our pastures. Slowly making it's way into another. What do we spray to kill it and other weeds but not grass? Also tim...
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What will kill this weed in our pastures? #894309
Asked March 13, 2025, 12:40 PM EDT
This weed has taken over one of our pastures. Slowly making it's way into another. What do we spray to kill it and other weeds but not grass? Also time frame of application.
Montcalm County Michigan
Expert Response
It is a little challenging to make out the plant in question here, but I believe it is red sorrel (Rumex acetosella), which is a common weedy problem in pastures. Red sorrel is an introduced, perennial weed with a yellow taproot that can reproduce by both seed and rhizomes, underground stems. As more leaves develop in the rosette, they will take on more of an arrowhead shape, which is characteristic of this species. Flowering stems have few leaves, reddish seedheads at maturity.
The real underlying problem with this weed is low soil pH. These plants are a good indicator that this is an issue. Low pH does not favor the growth of your grass species and allows this and other weeds that can tolerate low pH to invade. I would highly recommend soil testing your pastures if that has not been done lately. You can find more information on soil testing here: https://www.canr.msu.edu/news/soil-testing-returns-through-msu-extension The results will come with recommendations to remediate any issues.
Control of this weed with an herbicide would need to happen when it is >50F outside and before the plants are starting to flower. There are a few selective options for broadleaf weeds in grass pastures, including Crossbow, GrazonNext HL, and Milestone. A full listing with rates and further details is available in the MSU Weed Control Guide for Field Crops Forage Grass section: https://www.canr.msu.edu/weeds/extension/2025-Weed-Guide/2025_Weed_Guide_Web_Forages.pdf The initial table listing all the options starts on page 109, with details in the pages that follow. With any pesticide application it is critical to read and follow all labeled instructions to ensure maximum efficacy as well as environmental and personal safety.
You population has produced numerous seeds over the years, so following successful control it will be important to reestablish desired species (see labels for any limitation/timing information on replanting) and scout for new weeds emerging from the soil seedbank.
If you have any questions, please let me know.
The real underlying problem with this weed is low soil pH. These plants are a good indicator that this is an issue. Low pH does not favor the growth of your grass species and allows this and other weeds that can tolerate low pH to invade. I would highly recommend soil testing your pastures if that has not been done lately. You can find more information on soil testing here: https://www.canr.msu.edu/news/soil-testing-returns-through-msu-extension The results will come with recommendations to remediate any issues.
Control of this weed with an herbicide would need to happen when it is >50F outside and before the plants are starting to flower. There are a few selective options for broadleaf weeds in grass pastures, including Crossbow, GrazonNext HL, and Milestone. A full listing with rates and further details is available in the MSU Weed Control Guide for Field Crops Forage Grass section: https://www.canr.msu.edu/weeds/extension/2025-Weed-Guide/2025_Weed_Guide_Web_Forages.pdf The initial table listing all the options starts on page 109, with details in the pages that follow. With any pesticide application it is critical to read and follow all labeled instructions to ensure maximum efficacy as well as environmental and personal safety.
You population has produced numerous seeds over the years, so following successful control it will be important to reestablish desired species (see labels for any limitation/timing information on replanting) and scout for new weeds emerging from the soil seedbank.
If you have any questions, please let me know.
