Crabgrass and Dallisgrass: Telling Them Apart and Stopping Them in OKC

Fantastic Lawn • May 2026 • Oklahoma City, OK

Short Answer: Crabgrass and dallisgrass are often confused but are different plants that need different treatments. Crabgrass is an annual that germinates each spring, grows in a low spreading pattern, and dies at first frost. Dallisgrass is a perennial that survives winter, grows in distinct upright clumps with thick stems, and is much harder to kill. Pre-emergent stops crabgrass effectively. Dallisgrass requires repeated post-emergent applications and often dedicated spot treatment to control. Mistaking one for the other wastes treatment and lets the actual problem keep spreading. Here is how to tell them apart and stop each one for real.

If you have grassy weeds in your Oklahoma City, Edmond, or Norman lawn that look out of place, you are probably dealing with either crabgrass or dallisgrass. They get confused for each other constantly because they share some traits: both are wider-bladed than your turf grass, both grow in clumps or spreading patterns, and both stand out visually from a healthy Bermuda or fescue lawn.

The treatments are different though, and that is where the confusion costs homeowners money. A pre-emergent program that handles crabgrass beautifully will not touch dallisgrass. A spot post-emergent that kills crabgrass will barely make dallisgrass flinch. So getting the identification right is the first real step toward solving the problem.

How to Identify Crabgrass

Crabgrass has wider, lighter green blades than your turf grass. The plant grows from a central point and spreads outward in a low, prostrate pattern, like spokes from a wheel hub. Mature crabgrass produces seed heads that look like little fingers radiating from a single point.

Crabgrass is an annual. It germinates from seed each spring (typically when soil temperatures hit 55 degrees consistently), grows aggressively through summer, sets seed, and dies at first frost. Whatever crabgrass is in your lawn this year came from seed in the soil, and whatever lives long enough to set seed produces next year’s problem.

Crabgrass roots are shallow and easy to pull. The whole plant comes up cleanly with a quick tug if you grab the central point.

How to Identify Dallisgrass

Dallisgrass has thicker, darker green blades than crabgrass and a more upright growth habit. It forms distinct clumps rather than spreading flat. The seed head is much taller (sometimes 3 feet or more in unmowed lawns) and looks different: a long stem with several spike-like branches arranged in a Y or fan pattern.

Dallisgrass is a perennial. It survives winter and comes back from the same plant year after year, getting larger and more established each season. Once dallisgrass is in a lawn, it tends to spread because the existing clumps put out more seed and produce rhizomes.

The roots are deep and tough. Pulling dallisgrass is much harder than pulling crabgrass and usually leaves enough root in the soil for the plant to regrow.

Why Pre-Emergent Works on Crabgrass But Not Dallisgrass

Pre-emergent herbicides create a barrier in the soil that stops germinating seeds. Crabgrass relies entirely on seed germination each spring, so a properly timed pre-emergent prevents most of the crabgrass population.

Dallisgrass also produces seed, but established plants regrow from existing roots regardless of whether new seed germinates. Pre-emergent does nothing to existing dallisgrass clumps. You can have perfect pre-emergent coverage and still have all your dallisgrass back next year because it survived as a perennial.

This is why properties with dallisgrass often have homeowners frustrated with their lawn service: "We applied pre-emergent and the grassy weeds came back." The pre-emergent did its job on crabgrass. Dallisgrass is a different problem.

Treating Crabgrass

The best crabgrass control is preventative pre-emergent applied at the right soil temperature. In OKC, that timing is typically late February through mid-March, when soil temperatures are warming but before they cross 55 degrees consistently.

For crabgrass that breaks through (which happens), a post-emergent product like quinclorac or mesotrione applied while the crabgrass is young (3 leaves or fewer per plant) gives 80 to 90 percent control. Older, tillered crabgrass is harder to kill and may need a second application.

Long term, thicker turf is the real answer. Crabgrass needs sun on bare soil to germinate. A dense, healthy lawn shades the soil and prevents most germination even with weak pre-emergent. Improving turf density through fertilization, proper mowing height, and good watering reduces crabgrass pressure year after year.

Treating Dallisgrass

Dallisgrass is harder. The most effective approach involves repeated applications of MSMA (where it is still legal for spot use on certain grass types) or newer products like Celsius WG or Tribute Total, which provide selective control on Bermuda lawns.

Multiple applications spaced 2 to 3 weeks apart are usually needed. Even with consistent treatment, dallisgrass control rates are often only 60 to 80 percent in a season. You may need 2 to 3 seasons of consistent attention to fully clear a heavy infestation.

Spot treatment with a non-selective herbicide (glyphosate) kills individual dallisgrass plants reliably but also kills the surrounding lawn, leaving bare spots that need to be reseeded or plugged. This is sometimes the right approach for isolated clumps.

Prevention Going Forward

Once you have controlled both, prevention focuses on:

Maintaining thick, dense turf that crowds out new germination of either weed. Fertilization, proper mowing, and good watering matter most.

Keeping pre-emergent on schedule each spring to prevent new crabgrass.

Spot-treating any new dallisgrass clumps as soon as they appear, before they establish and spread.

Repairing bare spots quickly. Bare soil invites both weeds. A lawn that fills in damaged areas fast has less weed pressure overall.

Common Identification Mistakes

A few other plants get mistaken for one of these two:

Tall fescue clumps in a Bermuda lawn look out of place but are darker green and tighter clumped than dallisgrass. Selective herbicides for grassy weeds will damage fescue, so identification matters.

Goosegrass looks similar to crabgrass but with a lighter, almost white center. Treatment is similar to crabgrass.

Nutsedge has a triangular stem and a much narrower blade than either crabgrass or dallisgrass. Different chemistry needed entirely.

If you are unsure, take a photo of a single plant pulled with roots and send it to us. We can usually identify from the photo alone.

What to Do Next

If you have grassy weeds in your OKC, Edmond, or Norman lawn and you want to know what you are actually dealing with, we are glad to come identify them and put together a treatment plan that matches what is actually growing. Reach out anytime.