Getting rid of dallisgrass takes repeated effort: dig out small clumps fully, spot-treat large ones with herbicide in fall, and reseed bare spots.
Dallisgrass is one of the toughest weeds a lawn can host, and it earns that reputation. It forms dense, coarse clumps that stand out against fine turf, spreads by seed and underground rhizomes, and shrugs off a single spraying. The reason most control attempts fail is that they treat it like an annual weed. Dallisgrass is a perennial that needs a season-long strategy, not one weekend of effort.
The good news is that a solid plan works. If you catch it early, you can dig it out. If it has spread, a few well-timed herbicide applications will wear it down. The key is matching the approach to how bad the infestation is and staying consistent.
Why Is Dallisgrass So Hard To Kill?
Dallisgrass stores energy in underground rhizomes and a deep root system. Pulling the top growth leaves those roots behind, and the plant simply regrows. It also produces seed heads through most of the growing season, so a single missed plant can seed the whole yard.
This biology drives everything about control. Your job is to remove the entire plant, roots included, or to exhaust the plant’s energy reserves through repeat herbicide applications so it cannot regrow.
The Best Nonchemical Control: Dig It Out Completely
For young plants and small patches, a shovel beats any spray. The goal is removing the whole clump, not just the leaves. Use a shovel to cut a circle around the plant and lift the entire root mass out of the ground. Backfill the hole with soil and reseed right away so bare soil doesn’t invite new weeds back.
This method works best when the soil is damp, which makes the roots pull free more cleanly. It also works best before the plant sets seed. Check the area again in a few weeks and pull any regrowth from root fragments you missed.
Spraying Dallisgrass: The Timing That Actually Works
When infestations are too large to dig, herbicides are the practical route, but the timing matters almost as much as the product. Extension sources agree that repeat applications beat a single spray. Texas A&M recommends at least three sequential post-emergence applications. The University of Tennessee says multiple applications over two years may be needed for adequate control.
Here is the timing window that gives you the best odds:
- First post-emergence application in fall: Wait until after September and until the average 24-hour air temperature stays below 72°F for three straight days.
- Second application 4 to 6 weeks later: This catches plants that survived the first pass.
- Third application in spring: Texas A&M suggests mid-to-late April for better control.
- Pre-emergence option: The University of California’s IPM program suggests applying a pre-emergent herbicide in late winter or early spring, before the seed germinates.
Spot-spraying with a nonselective herbicide like glyphosate will kill dallisgrass, but it also damages the turf around it, leaving yellow or dead spots until the grass recovers. For selective control in lawns, products containing mesotrione or fluazifop are commonly cited; the right choice depends on your turf species, so a local extension recommendation is worth getting.
If you are deciding between herbicide options that work on dallisgrass, check the label’s turf-species compatibility before you buy.
Prevention: Stop It From Coming Back
A dense, healthy lawn is the best defense. Dallisgrass takes hold in thin turf and open soil, so keep your grass thick by mowing at the right height, watering deeply but less often, and fertilizing on a schedule that fits your region. The UC IPM dallisgrass guidance stresses that maintaining a competitive lawn is the foundation of long-term control.
Fill bare spots promptly with seed or sod. Open soil is an open invitation.
Common mistakes that cause regrowth include leaving root pieces in the ground, spraying only once, applying at the wrong time of year, and skipping the reseeding step. Each one is a small gap in the plan that dallisgrass will find.
Getting rid of dallisgrass is a slow, steady process, not a quick fix. Dig the small clumps, spray the big patches on schedule, keep the lawn thick, and fill the gaps. Stick with it through the season, and the dallisgrass will run out of energy before you run out of patience.
FAQs
What kills dallisgrass permanently?
No single treatment kills it permanently. Digging out the complete root mass works for small clumps. For larger patches, plan on three sequential post-emergence herbicide applications: the first in fall, a second 4 to 6 weeks later, and a third in spring. A dense, healthy lawn then keeps it from returning.
Does vinegar kill dallisgrass?
Household vinegar burns the leaves it touches but rarely kills the roots or rhizomes, so the plant regrows. Horticultural vinegar is stronger but still inconsistent on established perennials. You will get far better results with a labeled herbicide applied at the right time of year.
How do you identify dallisgrass in a lawn?
Dallisgrass forms distinct coarse clumps with thick, wide blades and seed heads featuring several finger-like branches. It stands out against fine-textured fescue or bluegrass. Unlike crabgrass, dallisgrass is a perennial, so the same clump returns year after year unless you remove the roots.
References & Sources
- University of California Agriculture and Natural Resources. “Dallisgrass.” UC IPM’s guide to identification, prevention, and control timing.
- Texas A&M AgriLife Extension. “Dallisgrass Control in Turfgrass.” Recommends three sequential post-emergence applications for effective control.
- University of Tennessee Extension. “Dallisgrass Control.” Notes that multiple applications over two years may be required.