How to Get Rid of Broomsedge for Good

Broomsedge takes hold because the soil invites it, so the only way to eliminate it permanently is to change the soil conditions that give it an advantage and then establish aggressive competing vegetation that keeps it from returning. No single spray or mowing pass will do the job alone. This native warm-season grass thrives in acidic, nutrient-poor ground and actively suppresses neighboring plants through chemical compounds it releases into the soil, which is why a lasting fix requires a combination of soil correction, physical disruption, fertilization, and reseeding.

Why Broomsedge Keeps Coming Back

Broomsedge (Andropogon virginicus) is the tawny, broom-like bunch grass that turns neglected pastures and roadsides golden brown every fall. Livestock won’t touch it, and it steadily displaces the forages they will eat. But broomsedge isn’t invading healthy ground. It’s filling a vacancy created by poor soil.

The soils where broomsedge dominates share a consistent profile: low pH, low phosphorus, and often elevated aluminum levels.¹ Most tall fescue pastures in the mid-South and Southeast that develop broomsedge problems sit on acidic, phosphorus-starved ground.² Years of grazing without replacing nutrients, skipping lime applications, or letting pH drift below 5.5 create conditions where desirable grasses struggle and broomsedge steps in. If you kill every broomsedge plant in a field but leave the soil unchanged, the same conditions that favored broomsedge will still be there, and new seedlings will germinate from a plentiful seed bank.

The Underground Partnership That Gives Broomsedge Its Edge

One reason broomsedge handles lousy soil better than your forage grasses is a partnership happening below the surface. Broomsedge forms tight relationships with certain soil fungi that extend its root network and dramatically improve its ability to scavenge phosphorus in low-nutrient conditions. Research has shown that these fungal partners greatly enhanced broomsedge growth when phosphorus was scarce but offered no meaningful benefit when phosphorus was readily available.¹ In other words, the fungi help broomsedge exploit the exact soil conditions where your fescue, bermudagrass, or clover are starving.

Compared to plants without the fungal association, broomsedge with active fungal partners used phosphorus more efficiently and maintained nearly constant tissue nutrient concentrations across a range of low-phosphorus conditions.¹ This biological adaptation is a major reason broomsedge colonizes degraded and infertile sites so successfully. When you raise soil phosphorus through fertilization and liming, you neutralize this advantage. Broomsedge doesn’t gain anything extra from its fungal partners in fertile soil, while the improved conditions let competitive forages finally grow to their potential.

How Broomsedge Poisons Its Neighbors

Broomsedge doesn’t just tolerate bad soil — it makes life harder for surrounding plants through chemical warfare. Extracts from broomsedge roots and shoots inhibit the germination and growth of multiple species. Even small amounts of decaying broomsedge tissue mixed into soil significantly stunted the growth of key pasture legumes like white clover and lespedeza, and also suppressed other grasses.³

This allelopathic effect is one reason broomsedge forms dense, expanding patches rather than scattering evenly across a field. Dead material from previous seasons accumulates around the base of each clump, releasing growth-inhibiting compounds that discourage competitors from establishing nearby. For you, this means that simply broadcasting seed into a broomsedge stand without first removing or disrupting the existing thatch and root mass will probably fail. The allelopathic compounds in the decaying plant matter suppress new seedlings before they get a foothold.

Tillage as a Reset

If your field has a serious broomsedge infestation, mechanical disruption is the most immediately effective physical tool. Research on broomsedge-infested bermudagrass pastures in Oklahoma found that a single spring tillage pass reduced broomsedge plant density by about 70% in the first year and stem density by roughly 90% by the second year compared to unfertilized, undisturbed plots.⁴

Tillage works against broomsedge for several reasons at once. It physically destroys the perennial crown of each bunch, disrupts the fungal network in the root zone, and buries or scatters the allelopathic thatch layer. The key word in that research is “one-time.” This isn’t about repeated plowing season after season. A single thorough disking or chisel-plowing pass in spring, timed when broomsedge is just resuming growth, can devastate established stands.

There are clear limitations. Tillage isn’t practical on steep slopes, rocky ground, or fields with established trees you want to keep. It also leaves bare soil that can erode if you don’t follow up quickly with seeding. And tillage alone, without soil correction and reseeding, just creates open ground that broomsedge will happily recolonize from the seed bank.

Fertilization and Liming to Shift the Competitive Balance

The most reliable long-term strategy against broomsedge is improving soil fertility so desirable grasses outcompete it. Broomsedge is a poor competitor in fertile soil. It’s adapted to win in nutrient deserts, and when you add fertility, the plants that can use those nutrients grow aggressively enough to shade broomsedge out.

Nitrogen fertilization drives this shift most visibly. In the Oklahoma study, applying 100 pounds of nitrogen per acre cut broomsedge stem density by about half in the second year, and doubling the rate to 200 pounds per acre reduced it by nearly 70%.⁴ The nitrogen didn’t kill broomsedge directly — it fueled bermudagrass growth, which then crowded broomsedge out through competition for light and space. This is an important distinction. The fertilizer isn’t a broomsedge herbicide. It’s a competitive advantage for the grasses you actually want.

Nitrogen alone isn’t enough. Phosphorus and potassium should be applied according to soil test recommendations, because the low-phosphorus conditions that broomsedge exploits need to be corrected at the same time. Liming to bring soil pH up to at least 6.0, and ideally 6.5 for most cool-season forages and legumes, is equally critical. Research on tall fescue pastures in Missouri specifically investigated whether lime or phosphorus was more important for limiting broomsedge, and both contribute to making conditions unfavorable for broomsedge and favorable for fescue.²

The first year can feel discouraging. In the Oklahoma study, nitrogen rates had no effect on broomsedge density during year one.⁴ The competitive displacement takes a full growing season for desirable grasses to fill in and begin truly suppressing broomsedge. Patience is part of the strategy.

Why Herbicides Are Not the Easy Answer

If you’re hoping a single herbicide application will solve your broomsedge problem, the research is sobering. Broomsedge is a grass, and most broadleaf herbicides do nothing to it. The selective herbicides that target grasses present their own challenges.

Imazapic, a herbicide sometimes used for warm-season grass management, proved essentially useless against broomsedge in field trials. Researchers found that broomsedge’s target enzyme was roughly 100 times less susceptible to imazapic than bermudagrass’s, meaning the herbicide would damage your bermudagrass long before it touched the broomsedge. In field experiments, imazapic provided no control of broomsedge whatsoever.⁵

MSMA, an organic arsenical herbicide, did show strong results, controlling broomsedge by about 80% at 12 months after initial treatment.⁵ However, MSMA’s availability has been heavily restricted by the EPA due to concerns about arsenic contamination, and it’s no longer registered for most turfgrass and pasture applications. Even where it remains available for limited uses, relying on an arsenic-based product as your primary broomsedge tool is not a viable long-term plan.

Glyphosate will kill broomsedge, but it’s nonselective and takes everything else in the field with it. That makes it a renovation tool, not a management tool. You’d use it as part of a complete field kill-and-reseed approach. For spot treatments of isolated broomsedge clumps in an otherwise healthy pasture, careful glyphosate application with a wick applicator or shielded sprayer can pick off individual plants without destroying surrounding grass. This is labor-intensive and only practical when broomsedge is scattered rather than dominant.

Establishing Competitive Forages

Once you’ve disrupted the existing broomsedge stand and corrected the soil, you need aggressive competing vegetation in place fast. Bare, corrected soil is an open invitation for broomsedge to return from its seed bank, and broomsedge produces enormous quantities of wind-dispersed seed every fall.

Establishing cool-season forages into broomsedge-infested pastures increases forage quality and extends the grazing season, providing economic motivation beyond just broomsedge suppression.⁶ In warm-season areas, bermudagrass is the standard competitor because it forms a dense sod that, when properly fertilized, leaves little room for broomsedge to germinate. In cooler regions or transition zones, tall fescue fills the same role. Adding legumes like white clover or red clover to the mix serves double duty: the legumes fix nitrogen, reducing your fertilizer costs over time, and increase ground coverage.

Timing and method of establishment matter. Drilling seed into a prepared seedbed gives better results than broadcasting onto undisturbed ground, partly because drilling places seed below the layer of allelopathic residue that may still be present. If you’re overseeding into an existing thinned stand rather than doing a full renovation, mowing or burning the broomsedge stubble first removes the thatch and lets light reach your new seedlings.

Prescribed Fire and Its Limits

Burning broomsedge-infested fields is a tempting idea, and prescribed fire does have a role, but it’s more limited than you might expect. Broomsedge is a warm-season grass that evolved with fire on the landscape. A single burn removes the dead top growth and thatch but doesn’t kill the root crowns. Broomsedge typically regrows vigorously after fire, sometimes more aggressively than before, because the burn clears competing cool-season vegetation and releases a flush of nutrients in the ash.

Where fire genuinely helps is as a preparation step. Burning in late winter or early spring removes the heavy thatch layer along with some of its allelopathic load, warms the soil surface, and creates a window for tillage, herbicide application, or overseeding. In the Oklahoma pasture research, fire was tested alongside tillage and fertilization as part of integrated management, and the researchers found that tillage combined with fertilization produced the dramatic reductions in broomsedge, while fire alone wasn’t the decisive factor.⁴ Fire cleans the slate, but what you do in the weeks after burning determines whether broomsedge comes back or desirable grasses take over.

A Realistic Timeline for Renovation

Getting rid of broomsedge is not a one-season project. A realistic timeline for a heavily infested pasture looks roughly like this:

Fall before renovation: Soil test the field. Apply lime based on results. Lime takes months to react fully with the soil, so fall application gives it time to adjust pH before spring planting.
Late winter or early spring: Burn or mow the broomsedge thatch if conditions allow. Follow with tillage to destroy crowns and disrupt the root zone.
Spring: Apply phosphorus and potassium according to your soil test. Seed your chosen forage by drilling or broadcasting onto a prepared seedbed. Apply nitrogen to fuel the new stand.
Year one growing season: Expect broomsedge to persist. The new forage needs time to establish. Mow high to prevent broomsedge from going to seed if possible, without scalping the new grass.
Year two: Apply maintenance fertilizer. This is when you should see substantial broomsedge decline as the competing forage fills in. Spot-treat surviving clumps if they’re isolated enough for targeted herbicide.
Year three and beyond: Maintain soil fertility with regular testing and appropriate applications every two to three years. A thick, well-fertilized stand of desirable forage is the long-term barrier that keeps broomsedge from returning.

The pattern that causes broomsedge to return year after year is the same one that let it establish in the first place: soil fertility declining gradually over time while nobody notices until broomsedge is already dominant. A soil test every two to three years and prompt correction of pH and nutrient levels is the cheapest insurance against a repeat infestation.

When Broomsedge Is Worth Keeping

Broomsedge isn’t universally a pest. In wildlife management, it provides excellent nesting cover for ground-nesting birds like bobwhite quail and various sparrows. Its bunch-growth habit creates the kind of open structure at ground level that chicks need to move through while staying hidden from predators overhead. On severely degraded sites like reclaimed strip mines, broomsedge is one of the first native plants to colonize and begin stabilizing the soil, thanks to those fungal partnerships that let it thrive where almost nothing else can.¹

If you have a portion of your property managed for wildlife habitat rather than livestock production, maintaining some broomsedge cover can be a genuine asset. The same traits that make it a nuisance in a pasture — persistence in poor soil, dense bunch structure, prolific seed production — make it valuable for conservation. Plenty of quail habitat managers deliberately foster broomsedge in field borders and fallow strips. The real question isn’t whether broomsedge is bad in some absolute sense, but whether it’s occupying land where you need something else to grow.

1
PubMed. Arbuscular mycorrhizal fungi alter phosphorus relations of broomsedge (Andropogon virginicus L.) plants
2
Crop, Forage & Turfgrass Management. Lime or Phosphorus: Which is Best to Limit Broomsedge in Lift Fescue Pastures?
3
American Journal of Botany. Allelopathic Effects of Andropogon Virginicus and Its Persistence in Old Fields
4
Forage & Grazinglands. Using Prescribed Fire, Tillage, and Fertilizer to Manage Broomsedge‐Infested Pastures
5
Weed Science. Biochemical Effects of Imazapic on Bermudagrass Growth Regulation, Broomsedge (Andropogon virginicus) Control, and MSMA Antagonism
6
Agronomy Journal. Methods of Establishing Annual Ryegrass and Clover into Broomsedge‐Infested Pastures