Quick facts
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Identify what type of weeds are in your pasture: annuals, biennials or perennials.
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Control consists of mechanical (e.g. mowing), chemical (e.g. herbicide) and cultural (e.g. overseeding) methods.
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Pasture management is the best way to prevent weed growth and infestations.
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There are no selective herbicides for controlling weeds in grass-legume mixed pastures.
Pasture weed control is hard for most horse owners. Many grass pastures in the Midwest contain broadleaf and grassy weeds. Compared to ideal forage species, weeds are
Less palatable
Less nutritious
Lower yielding
Here are some steps for managing weeds in grass pastures.
1. Identify the weed type
There are three types of weeds.
Annuals: live for one year
Biennials: live for two years
Perennials: live for three or more years
2. Control the weeds
Note: Select herbicides carefully and only apply them if necessary. Herbicides labeled for pasture use aren’t harmful to horses if you apply them at the recommended rate and follow all directions. Make sure to read and follow the herbicide label and comply with grazing restrictions.
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Mechanical weed control, such as mowing, is effective for control if done prior to flowering and seeding.
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Herbicide use is most effective when applied in the spring to small growing weeds.
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Herbicides is most effective for first-year biennials. When you apply herbicides the second year, it’s most effective when applied before flowering.
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Mowing prior to seeding is effective for control the second year. Mowing isn’t an option for the first year as the rosettes are too close to the ground.
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Control requires mechanical (e.g. mowing), chemical (e.g. herbicide) and cultural (e.g. overseeding) weed control.
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Mowing alone may take a few growing seasons to be effective. It may never result in complete control.
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Herbicides alone, or a single application, likely won’t control perennial weeds. Apply herbicides between August 1st and September 15th for the best control.
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Applying herbicides in the spring or mowing during the summer can control weed growth until fall.
3. Prevent weed growth
A well-managed pasture will out-compete most weed species.
Avoid overgrazing your pastures.
Test soil pH and fertility every three years and fertilize and lime if needed.
Rest the pasture to allow for plant regrowth after each grazing event.
Mow, drag and apply herbicides during the resting period.
Reviewed in 2023