The label is the law. Rates and restrictions below are taken from the product labels listed under Sources. Your product's own label governs; read it before you mix or apply. Mixing calculator · Disclaimer
- Active ingredient
- Oryzalin
- Chemical class
- Dinitroaniline (sulfanilamide) herbicide; WSSA Group 3 mitosis inhibitor that blocks microtubule formation in germinating seedlings.[2][1]
- Mode of action
- WSSA Group 3: Mitosis inhibitors (dinitroanilines)[2][1]
- Signal word
- Surflan AS Specialty Herbicide: Caution[1]
Where not to use oryzalin
Keep it off cool-season lawns, putting greens and tees, and lawns with dichondra. It also shouldn't go on ornamental beds where runoff could reach lawn areas.[1]
Skip seedling, cutting and transplant beds, unrooted liners, pots under 4 inches wide, and ground covers that aren't yet well rooted. The label also reports injury on slender deutzia, Douglas-fir and Techny arborvitae.[1]
Reseeding and overseeded bermudagrass
Delay reseeding for at least 90 to 120 days after an application, and use a higher seeding rate with good seed-to-soil contact when you do. A spring application on overseeded bermudagrass will thin the winter grass.[1]
Where it is used
It stays stable on the soil surface for up to 21 days, but needs at least ½ inch of rain or sprinkler irrigation to activate. Without activation in that window, weed control may be erratic.[1]
It won't control weeds that are already up. Pull or shallowly cultivate existing weeds, 1 to 2 inches deep, before or after applying.[1]
Do core aeration or verticutting before applying, not after. Apply only to healthy, well-rooted turf; stressed or newly sprigged and sodded grass can be injured.[1]
The spray is orange and can stain surfaces. Rinse with water or wash promptly if the discoloration is a problem.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Surflan AS Specialty Herbicide[1] | UPL NA Inc. | 70506-44 | 40.4% | aqueous suspension (4.0 lb oryzalin per gallon) | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Surflan AS Specialty Herbicide | Landscape ornamentals, field-grown and container-grown ornamentals | Crabgrass, goosegrass, foxtails, annual bluegrass, chickweed, henbit, purslane and other annual weeds | 1.5–3 fl oz product per 1,000 sq ft[1] 1.5 fl oz gives about 2 to 4 months of control, 2.2 fl oz 3 to 6 months and 3 fl oz 4 to 8 months. In landscapes, wait at least 2 months (low rate) or 4 months (higher rates) between applications. |
| Surflan AS Specialty Herbicide | Established warm-season turf (bermudagrass, St. Augustinegrass, centipedegrass, zoysiagrass, bahiagrass, buffalograss) and tall fescue in warm-season areas | Crabgrass, goosegrass, foxtails, annual bluegrass, henbit, chickweed and other annual weeds | 1–1.5 fl oz product per 1,000 sq ft[1] Equal to 1.5 to 2 qt per acre, at least 3 months apart, with no more than 6 qt per acre per year. In Florida, use 1.5 qt per acre up to three times a year. |
Safety and environmental hazards
People
Signal word CAUTION: causes eye irritation, and prolonged or repeated contact may cause allergic reactions in some people. Handlers wear long sleeves, long pants, waterproof gloves, shoes and socks.[1]
Pets
For non-farm uses, keep all people, children and pets out of the treated area until the spray has dried.[1]
Bees and pollinators
The label carries no bee warning, but says the product is toxic to plants and drift can harm pollinator forage and habitat next to the treated area.[1]
Fish and water
Toxic to fish; don't apply to water or where surface water is present. Oryzalin can leach to groundwater on permeable soils, especially where the water table is shallow.[1]
Common questions
- Can I use oryzalin on a fescue or bluegrass lawn?
- No. The label says not to apply it to cool-season turfgrass. Tall fescue is allowed only in warm-season areas, using split 1.5 quart per acre applications.[1]
- How soon does oryzalin need water after I apply it?
- Within 21 days. It needs at least half an inch of rain or irrigation to activate.[1]
- How long should I wait to reseed after oryzalin?
- At least 90 to 120 days, according to the Surflan AS label.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Surflan AS Specialty Herbicide label, EPA Reg. No. 70506-44 (EPA-stamped, Nov. 6, 2025).” www3.epa.gov/pesticides/chem_search/ppls/070506-00044-20251106.pdf (accessed 2026-10-06)
- Weed Science Society of America, “Summary of Herbicide Mechanism of Action According to the Weed Science Society of America.” wssa.net/wp-content/uploads/WSSA-Mechanism-of-Action.pdf (accessed 2026-10-06)