The weeds that give us the most grief in a centipede or St. Augustine lawn around Monticello aren't broadleaf weeds at all. They're other grasses. Torpedograss and common bermuda both spread aggressively into fine turf, and because they're grasses just like your lawn, there's no easy selective spray that removes them and leaves your centipede standing. These are the two calls where we have to be the most honest about what's actually possible.
Why grassy invaders are so hard
A broadleaf weed like dollarweed or clover is chemically different enough from your turf that products exist to kill the weed and spare the grass. Grass-on-grass is different. The things that reliably kill torpedograss or bermuda tend to kill centipede and St. Augustine right along with them. So control isn't about finding the magic bottle. It's about understanding each invader's biology and picking the least-bad path. Let's take them one at a time, because they don't behave the same way.
Torpedograss: the one that spreads underground
Torpedograss earns its name. It spreads by tough, pointed rhizomes that push horizontally underground, and the growing tips are literally sharp enough to punch through roots and even weak spots in pipe. It loves moisture and typically marches in from wet ditches, pond edges, and the low soggy corners of a yard. Once it's established, it is one of the hardest weeds in North Florida to fully eliminate.
How to identify it
- Stiff, upright, blue-green blades with a coarser feel than centipede.
- Waxy leaves that often stand at an angle rather than lying flat.
- Those aggressive rhizomes. Dig at the edge of a patch and you'll find white, pointed underground runners driving outward. That's the engine.
- It shows up near water first and works its way in from the wet edge of the property.
The realistic path
There is no reliable selective that clears torpedograss out of a lawn without harming your turf. Trying to spot-spray it with a broadleaf product just wastes a season. The honest approach is repeated non-selective glyphosate on the infested areas, applied per the label, followed by renovation once it's dead. Because torpedograss regrows from every rhizome fragment left in the soil, you plan on multiple glyphosate applications spaced out to catch the regrowth before you ever re-establish clean turf. Skip that patience and the rhizomes just push new shoots through your fresh sod. When you're ready to replant the cleared ground, our guide to sod installation in North Florida walks through doing it right. It's slow, it's frustrating, and it's the truth.
Bermuda invading centipede: a more workable fight
Common bermudagrass is the other grassy invader we see constantly, especially where a centipede yard backs up to a bermuda pasture, a roadside, or a neighbor's bermuda lawn. Bermuda spreads by both above-ground stolons and underground rhizomes, greens up aggressively, and outcompetes centipede in full sun. The good news is that bermuda gives you a real chemical option that torpedograss doesn't.
Sethoxydim can selectively suppress bermuda
Products built around sethoxydim can selectively suppress bermudagrass in centipede and St. Augustine lawns. That's a genuinely useful tool. A few things to understand before you reach for it:
- Obviously not for bermuda lawns. If your lawn is bermuda, this kills your lawn. It's only a tool when bermuda is the weed and centipede or St. Augustine is the desired turf.
- Plan on repeat applications. Bermuda's rhizomes let it push back, so the label will call for more than one treatment spaced out over the season. Suppression, not one-shot eradication.
- Read and follow the label to the letter. Rates, timing, spray intervals, and turf tolerances are all spelled out. Centipede is sensitive, so don't freelance the rate.
Where bermuda has completely dominated a patch, sethoxydim suppression may not be enough, and you're back to spot-killing with glyphosate and re-plugging with centipede. But for bermuda creeping in along an edge, sethoxydim over a season can hold it back and let your centipede reclaim ground.
Prevention beats both
Both of these invaders exploit weak, thin, or stressed turf and open edges. The single best defense is a dense, healthy centipede lawn that doesn't leave them an opening. That means getting centipede's care right, which is its own discipline since it hates over-feeding and scalping. Our centipede grass care guide covers keeping it thick, and correct cutting height matters more than people think, so read up on mowing height by grass type too. A few habits that keep these grasses from spreading:
- Keep clean, defined edges along ditches, fence lines, and the pasture side of the property. That's where both invaders enter.
- Don't drag rhizomes around. A mower deck that just rolled through a torpedograss or bermuda patch carries live fragments across your whole yard. Clean the deck before you move on, and mow infested areas last.
- Control the moisture. Torpedograss especially thrives in the soggy low spots, so fixing drainage and not overwatering removes its favorite habitat.
- Stay after new patches while they're small. A dinner-plate patch is a spot-treat. A quarter of the yard is a renovation.
It's worth knowing these aren't the only tough grassy invaders here. Bahiagrass throws its own coarse clumps and Y-shaped seedheads into the mix, and it needs its own approach, covered in our post on controlling bahiagrass. Correct ID always comes first.
The bottom line
Torpedograss and bermuda in a centipede lawn are among the hardest weed problems we deal with in Jefferson County, and anybody promising a quick selective fix is guessing. Torpedograss usually means repeated glyphosate and renovation. Bermuda gives you sethoxydim as a real suppression tool but still demands patience and repeat treatments. Both reward prevention far more than rescue.
If you've got a coarse grass creeping into your centipede and you're not even sure which one it is, that's exactly the call to make before you spray anything. Williams Total Lawn Care can walk the yard, identify the invader, and lay out an honest plan that fits the grass you want to keep. Get in touch and we'll take a look.