Plant Problem Diagnostic
Dallisgrass Identification and Control (Perennial, Not Crabgrass)
The short answer
Dallisgrass (Paspalum dilatatum) is a perennial clumping grass that forms coarse, loose bunches 1 to 5 feet tall and grows back in the same circular clumps year after year from a persistent crown and short rhizomes. Its seedhead is a tall stalk bearing three to six spike-like branches that often droop, with hairy spikelets in rows, and the seedheads are frequently infected by an ergot fungus that shows as black bodies and is toxic to livestock.
It is often confused with crabgrass, but the difference is fundamental: crabgrass is a soft-leaved summer annual that dies each winter, while dallisgrass is a stiff-leaved perennial that survives and regrows from its crown, so it cannot be waited out. In mowed turf, dallisgrass leaves are stiffer and the plant regrows from the same spot.
Because it is perennial with short rhizomes and a deep root system, it is one of the more difficult turf weeds to control: digging must remove the entire crown or it regrows, mowing fails, and selective chemical removal from desirable turf is difficult, so the best defense is preventing establishment with a dense, healthy lawn.
How to identify it
Look for coarse circular clumps. Dallisgrass grows in loose bunches 1 to 5 feet tall (shorter when mowed) that reappear in the same rings each year, on flattened stems with hairless nodes. The seedhead is the clearest sign: a tall terminal stalk with three to six (up to eight) spike-like branches arising from different points along it, often drooping, carrying hairy spikelets arranged in rows.
A frequent extra clue is the ergot fungus (Claviceps paspali) on the seedheads, appearing as dark or black bodies; it is toxic to grazing livestock. The flattened stems and hairless nodes help separate it from knotgrass, which has rounded stems and hairy nodes.
Dallisgrass, crabgrass, or bahiagrass?
The crabgrass mix-up is the common one, and it matters because the two are managed differently. In a mowed lawn the leaves look alike and both are dull green, but dallisgrass leaves are stiffer while crabgrass leaves are soft, and, decisively, dallisgrass is a perennial that regrows from the same crown while crabgrass is a summer annual that dies off each winter and returns from seed.
Dallisgrass can also be confused with bahiagrass (Paspalum notatum), a related warm-season perennial bunchgrass that also has short rhizomes. Both are Paspalum species, but dallisgrass is marked out by its tall, drooping, multi-branched seed stalks and the dark ergot bodies on the seedheads.
Why it is so hard to control
It is built to persist. As a perennial with short rhizomes and a deep root system, dallisgrass regrows in the same clumps every year, so mowing only removes the top and the seedheads re-form quickly from the surviving low crown. Hand-digging works only if you remove the entire crown and rhizomes; leave part behind and it returns.
Extension calls it one of the more difficult-to-control weeds in turfgrass, because selective removal of a perennial grass from a desirable grass lawn is genuinely difficult. That is why the emphasis is on prevention: maintain a dense, healthy turf year-round through proper mowing and fertilization to keep it from establishing. If you consider a herbicide, follow the product label and county Extension guidance, as no rates are given here.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- UC IPM - Dallisgrass (Weed Gallery) — Dallisgrass (Paspalum dilatatum) is a perennial grass that forms loose bunches growing 1 to 5 feet tall and blooms from May through November; it has flattened stems and hairless stem joints (nodes), and its flower head has three to six spikes that arise from different points along the stem and often droop; its seed heads are susceptible to an ergot fungus, Claviceps paspali, that is toxic to livestock when ingested; in mowed lawns it may be confused with crabgrass, but dallisgrass leaves are stiffer while crabgrass leaves are soft, and bahiagrass (P. notatum), a related warm-season perennial bunchgrass with short rhizomes, can also be confused with it.
- NC State Extension - Dallisgrass — Dallisgrass is a perennial weed with occasional and very short rhizomes; its seedhead is a raceme of hairy spikelets arranged in 4 rows on 3 to 8 alternate branches on tall terminal stalks up to 5 feet in unmowed situations; its leaf appearance is very similar to crabgrass with a dull green appearance; dallisgrass is one of the more difficult-to-control weeds in turfgrasses, perennial grass weeds such as dallisgrass are not desirable turfgrass under any conditions and selective control measures are usually difficult, so every effort should be made to prevent establishment by maintaining a dense, healthy turf year round through proper mowing and fertilization.