Lawn Care · Grassy Weeds
Dallisgrass comes back from its roots, so treat the clump, not the leaves.
To get rid of dallisgrass, dig out small clumps with their rhizomes, or spot-treat with an herbicide your lawn grass tolerates, starting in late summer and repeating four to six weeks later. Which product depends on your grass: foramsulfuron-based products in bermuda and zoysia, fluazifop in tall fescue, and careful glyphosate spot treatment where nothing selective is labeled. MSMA, the old standby, has been off-limits on home lawns since 2009.
LIFE CYCLE
Perennial, short thick rhizomes
BEST TIME TO TREAT
Late summer into fall
TYPICAL PROGRAM
2+ spot treatments, 4–6 weeks apart
MSMA ON HOME LAWNS
Cancelled by EPA in 2009
What dallisgrass is, and how to be sure you have it
Dallisgrass (Paspalum dilatatum) is a perennial grass weed. University of Tennessee Extension calls it arguably one of the hardest turf weeds to control in the state, and the reason is underground: it spreads by seed and by short, thick rhizomes, so the clump regrows from its base after the top is killed or mowed off.
Check these features before you buy anything, because the control plan for dallisgrass is different from the one for crabgrass:
- Color and texture. Coarse, gray-green leaves with an obvious midrib, growing as a rounded clump (LSU AgCenter).
- Base of the plant. Dig one up. Dallisgrass has short, knobby brown rhizomes with ring-like segments at the base. Crabgrass has a fibrous, annual root system and no rhizomes.
- Leaf collar. A tall, papery (membranous) ligule and no auricles, per NC State TurfFiles.
- Seedhead. A stalk with three to about eight side branches; the hairy seeds sit in rows along one side of each branch. LSU notes tiny black flower parts on those branches. UT says seed production can start as early as mid-June in Tennessee.
NC State warns that field paspalum and thin paspalum look very similar. If you are still unsure, compare yours against our crabgrass vs dallisgrass photos and the look-alikes in weeds that look like grass, or take a sample to your county extension office.
Why crabgrass products usually disappoint
Crabgrass is an annual: it dies each fall and has to start from seed. A pre-emergent and a summer crabgrass killer can manage it inside one season, as covered in our crabgrass killer tests. Dallisgrass doesn’t play by that calendar. It overwinters as a living crown and rhizomes, so a single spray that browns the leaves often just sets it back a few weeks.
A pre-emergent still has a small role. LSU AgCenter lists dithiopyr as a pre-emergent option that is safe in the four main warm-season grasses, because dallisgrass seeds germinate in spring and summer and start new clumps. It does nothing to clumps you already have.
Pick the herbicide by your lawn grass
The herbicide that kills dallisgrass without killing your lawn depends almost entirely on what your lawn is. The table below lists active ingredients only. Rates, mixing, adjuvants and grass-safety limits come from the product label, which is the legal instruction for that product. Several of these are professional products; read the label before you buy, and check that dallisgrass and your turf species are both listed on it.
| Your lawn grass | Active ingredients extension sources list | What to know |
|---|---|---|
| Bermudagrass | Thiencarbazone + foramsulfuron + halosulfuron (sold as Tribute Total); foramsulfuron (Revolver); pinoxaden (Manuscript); sulfosulfuron or trifloxysulfuron as spot treatments | Best-supported group. UT reports its best results from repeat late-summer spot treatments with Tribute Total, and says sulfonylurea results vary (UT SP642). |
| Zoysiagrass | Foramsulfuron; thiencarbazone + foramsulfuron + halosulfuron | LSU and the manufacturer list both for zoysia, while University of Arkansas says to use Tribute Total only in bermuda. Follow the current label. |
| Tall fescue | Fluazifop (Fusilade II; also sold for home lawns as Ornamec) | UT recommends fall applications three to four weeks apart with a surfactant, and not on drought- or heat-stressed fescue. |
| St. Augustinegrass or centipedegrass | No selective option in the sources we checked | LSU lists the selective products as not for these grasses. Dig small clumps; spot-treat with glyphosate and patch. |
| Kentucky bluegrass, ryegrass or mixed cool-season | No selective option in the sources we checked | Dig, or spot-treat with glyphosate and reseed the gap with your lawn’s seed mix. |
| Any lawn, as a last resort | Glyphosate (non-selective) | Kills any grass it touches. Paint or shield-spray individual clumps only. |
UT describes one timing trick for bermuda: spot-spray glyphosate after the bermuda has gone fully dormant but while the dallisgrass is still green. The window is roughly two weeks, so it only works if you are watching the lawn closely, and UT still advises a spring follow-up.
A two-season removal plan
Dallisgrass rarely disappears in one visit. This sequence pulls the extension advice into an order you can follow:
- Confirm the ID and mark every clump in early summer, when the seedheads make them easy to spot. Flags or a quick sketch save you from hunting for them in September.
- Dig what you can. For a handful of clumps, a sharp spade is the cheapest and safest control. Cut down and around each clump and lift it with the knobby rhizomes intact; University of Arkansas lists digging as an option for exactly this reason. Leftover rhizome pieces can resprout, so check the spot again in a few weeks.
- Keep seedheads from ripening. Mow often enough that stalks don’t mature, and bag clippings when seedheads are present so you aren’t spreading seed around the yard.
- Make the first spot treatment in late summer. The manufacturer of Tribute Total puts the first application between August 15 and September 30, while the dallisgrass is actively growing and not drought-stressed, with transition-zone lawns starting earlier (Envu). UT also says fall is generally the best time.
- Repeat four to six weeks later. Envu times this second application for when the dallisgrass starts to recover. UT notes multiple applications over two years may be needed.
- Check again next spring. Re-treat any clump that greens up, and fill the bare spots right away with seed or sod of your own grass so new dallisgrass seedlings have no room.
Long term, density is the real defense. LSU’s first line of defense is a dense, vigorous lawn, and it gives mowing heights and yearly nitrogen limits per 1,000 sq ft for warm-season lawns: bermuda 1 to 2 inches and up to 3 lb N, centipede 1 to 2.5 inches and up to 2 lb, St. Augustine 2.5 to 3 inches and up to 3 lb, and zoysia 1 to 2.5 inches and up to 2 lb (LSU AgCenter).
What happened to MSMA
For decades MSMA, an organic arsenical herbicide, was the standard dallisgrass treatment, and it still turns up in older advice and forum threads. According to the EPA, residential lawn use was cancelled in 2009, along with athletic fields and parks. It remains registered for limited uses: golf courses (spot treatments only, each spot no larger than 100 sq ft and no more than 25% of the acreage a year), sod farms, highway rights-of-way and cotton. Florida bars it except on cotton in specified counties.
Those remaining turf uses are under review too. EPA’s March 2021 proposed interim decision found the turf uses don’t currently meet the federal registration standard, with removal from labels on hold pending further review. For a homeowner the answer is simple: a lawn is not on any current MSMA label, and using a pesticide in a way its label doesn’t allow is illegal.
Stop spot-treating when dallisgrass is the lawn.
Spot treatments make sense for scattered clumps. When dallisgrass runs through a St. Augustine or centipede lawn, where no selective product is labeled, LSU’s advice is to kill the whole area with glyphosate and wait at least two weeks before preparing the soil and laying new sod. UT likewise says renovation may be the best option for very heavy infestations. Broadcasting glyphosate or reaching for MSMA to save a heavily infested lawn is the mistake to avoid.
If you would rather hand off a large infestation or a renovation, our lawn weed control page connects you with a lawn care company serving your area.
Dallisgrass FAQs
Can I just pull dallisgrass by hand?
Pulling usually snaps the leaves off and leaves the rhizomes. Dig instead: cut around the clump with a spade and lift the whole crown, then watch the spot for regrowth.
Will a crabgrass pre-emergent stop dallisgrass?
Only new seedlings. LSU lists dithiopyr as a pre-emergent option for warm-season lawns, but established clumps return from their rhizomes no matter what pre-emergent you use.
Does dallisgrass die in winter?
The top goes dormant, but it is a perennial and regrows from its crown and rhizomes in spring. That is why fall treatment, before dormancy, is the timing extension programs favor.
Is MSMA still legal for lawns?
No. EPA cancelled residential lawn use in 2009. MSMA is limited to golf courses, sod farms, highway rights-of-way and cotton, and even those turf uses are under review.
What kills dallisgrass in a St. Augustine lawn?
None of the selective options in the extension guides we checked are listed for St. Augustine. Dig scattered clumps, carefully spot-treat with glyphosate and patch, or renovate a heavily infested area.
How long does it take to get rid of dallisgrass?
Plan on at least one full season. A late-summer treatment, a second one four to six weeks later and a spring check is the usual minimum, and UT says some lawns need applications over two years.
Related guides
Sources: UT Extension SP642: Dallisgrass (2019) · LSU AgCenter: Dallisgrass · NC State TurfFiles: Dallisgrass · University of Arkansas Plants Database: Dallisgrass · EPA: MSMA (organic arsenical) status · Envu: Dallisgrass solution sheet (Tribute Total timing)
